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evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/__init__.py

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+__all__ = [
+    'vector',
+
+    'CoordinateSym', 'ReferenceFrame', 'Dyadic', 'Vector', 'Point', 'cross',
+    'dot', 'express', 'time_derivative', 'outer', 'kinematic_equations',
+    'get_motion_params', 'partial_velocity', 'dynamicsymbols', 'vprint',
+    'vsstrrepr', 'vsprint', 'vpprint', 'vlatex', 'init_vprinting', 'curl',
+    'divergence', 'gradient', 'is_conservative', 'is_solenoidal',
+    'scalar_potential', 'scalar_potential_difference',
+
+    'KanesMethod',
+
+    'RigidBody',
+
+    'linear_momentum', 'angular_momentum', 'kinetic_energy', 'potential_energy',
+    'Lagrangian', 'mechanics_printing', 'mprint', 'msprint', 'mpprint',
+    'mlatex', 'msubs', 'find_dynamicsymbols',
+
+    'inertia', 'inertia_of_point_mass', 'Inertia',
+
+    'Force', 'Torque',
+
+    'Particle',
+
+    'LagrangesMethod',
+
+    'Linearizer',
+
+    'Body',
+
+    'SymbolicSystem', 'System',
+
+    'PinJoint', 'PrismaticJoint', 'CylindricalJoint', 'PlanarJoint',
+    'SphericalJoint', 'WeldJoint',
+
+    'JointsMethod',
+
+    'WrappingCylinder', 'WrappingGeometryBase', 'WrappingSphere',
+
+    'PathwayBase', 'LinearPathway', 'ObstacleSetPathway', 'WrappingPathway',
+
+    'ActuatorBase', 'ForceActuator', 'LinearDamper', 'LinearSpring',
+    'TorqueActuator', 'DuffingSpring'
+]
+
+from sympy.physics import vector
+
+from sympy.physics.vector import (CoordinateSym, ReferenceFrame, Dyadic, Vector, Point,
+        cross, dot, express, time_derivative, outer, kinematic_equations,
+        get_motion_params, partial_velocity, dynamicsymbols, vprint,
+        vsstrrepr, vsprint, vpprint, vlatex, init_vprinting, curl, divergence,
+        gradient, is_conservative, is_solenoidal, scalar_potential,
+        scalar_potential_difference)
+
+from .kane import KanesMethod
+
+from .rigidbody import RigidBody
+
+from .functions import (linear_momentum, angular_momentum, kinetic_energy,
+                        potential_energy, Lagrangian, mechanics_printing,
+                        mprint, msprint, mpprint, mlatex, msubs,
+                        find_dynamicsymbols)
+
+from .inertia import inertia, inertia_of_point_mass, Inertia
+
+from .loads import Force, Torque
+
+from .particle import Particle
+
+from .lagrange import LagrangesMethod
+
+from .linearize import Linearizer
+
+from .body import Body
+
+from .system import SymbolicSystem, System
+
+from .jointsmethod import JointsMethod
+
+from .joint import (PinJoint, PrismaticJoint, CylindricalJoint, PlanarJoint,
+                    SphericalJoint, WeldJoint)
+
+from .wrapping_geometry import (WrappingCylinder, WrappingGeometryBase,
+                                WrappingSphere)
+
+from .pathway import (PathwayBase, LinearPathway, ObstacleSetPathway,
+                      WrappingPathway)
+
+from .actuator import (ActuatorBase, ForceActuator, LinearDamper, LinearSpring,
+                       TorqueActuator, DuffingSpring)

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/actuator.py

@@ -0,0 +1,992 @@
+"""Implementations of actuators for linked force and torque application."""
+
+from abc import ABC, abstractmethod
+
+from sympy import S, sympify
+from sympy.physics.mechanics.joint import PinJoint
+from sympy.physics.mechanics.loads import Torque
+from sympy.physics.mechanics.pathway import PathwayBase
+from sympy.physics.mechanics.rigidbody import RigidBody
+from sympy.physics.vector import ReferenceFrame, Vector
+
+
+__all__ = [
+    'ActuatorBase',
+    'ForceActuator',
+    'LinearDamper',
+    'LinearSpring',
+    'TorqueActuator',
+    'DuffingSpring'
+]
+
+
+class ActuatorBase(ABC):
+    """Abstract base class for all actuator classes to inherit from.
+
+    Notes
+    =====
+
+    Instances of this class cannot be directly instantiated by users. However,
+    it can be used to created custom actuator types through subclassing.
+
+    """
+
+    def __init__(self):
+        """Initializer for ``ActuatorBase``."""
+        pass
+
+    @abstractmethod
+    def to_loads(self):
+        """Loads required by the equations of motion method classes.
+
+        Explanation
+        ===========
+
+        ``KanesMethod`` requires a list of ``Point``-``Vector`` tuples to be
+        passed to the ``loads`` parameters of its ``kanes_equations`` method
+        when constructing the equations of motion. This method acts as a
+        utility to produce the correctly-structred pairs of points and vectors
+        required so that these can be easily concatenated with other items in
+        the list of loads and passed to ``KanesMethod.kanes_equations``. These
+        loads are also in the correct form to also be passed to the other
+        equations of motion method classes, e.g. ``LagrangesMethod``.
+
+        """
+        pass
+
+    def __repr__(self):
+        """Default representation of an actuator."""
+        return f'{self.__class__.__name__}()'
+
+
+class ForceActuator(ActuatorBase):
+    """Force-producing actuator.
+
+    Explanation
+    ===========
+
+    A ``ForceActuator`` is an actuator that produces a (expansile) force along
+    its length.
+
+    A force actuator uses a pathway instance to determine the direction and
+    number of forces that it applies to a system. Consider the simplest case
+    where a ``LinearPathway`` instance is used. This pathway is made up of two
+    points that can move relative to each other, and results in a pair of equal
+    and opposite forces acting on the endpoints. If the positive time-varying
+    Euclidean distance between the two points is defined, then the "extension
+    velocity" is the time derivative of this distance. The extension velocity
+    is positive when the two points are moving away from each other and
+    negative when moving closer to each other. The direction for the force
+    acting on either point is determined by constructing a unit vector directed
+    from the other point to this point. This establishes a sign convention such
+    that a positive force magnitude tends to push the points apart, this is the
+    meaning of "expansile" in this context. The following diagram shows the
+    positive force sense and the distance between the points::
+
+       P           Q
+       o<--- F --->o
+       |           |
+       |<--l(t)--->|
+
+    Examples
+    ========
+
+    To construct an actuator, an expression (or symbol) must be supplied to
+    represent the force it can produce, alongside a pathway specifying its line
+    of action. Let's also create a global reference frame and spatially fix one
+    of the points in it while setting the other to be positioned such that it
+    can freely move in the frame's x direction specified by the coordinate
+    ``q``.
+
+    >>> from sympy import symbols
+    >>> from sympy.physics.mechanics import (ForceActuator, LinearPathway,
+    ...     Point, ReferenceFrame)
+    >>> from sympy.physics.vector import dynamicsymbols
+    >>> N = ReferenceFrame('N')
+    >>> q = dynamicsymbols('q')
+    >>> force = symbols('F')
+    >>> pA, pB = Point('pA'), Point('pB')
+    >>> pA.set_vel(N, 0)
+    >>> pB.set_pos(pA, q*N.x)
+    >>> pB.pos_from(pA)
+    q(t)*N.x
+    >>> linear_pathway = LinearPathway(pA, pB)
+    >>> actuator = ForceActuator(force, linear_pathway)
+    >>> actuator
+    ForceActuator(F, LinearPathway(pA, pB))
+
+    Parameters
+    ==========
+
+    force : Expr
+        The scalar expression defining the (expansile) force that the actuator
+        produces.
+    pathway : PathwayBase
+        The pathway that the actuator follows. This must be an instance of a
+        concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``.
+
+    """
+
+    def __init__(self, force, pathway):
+        """Initializer for ``ForceActuator``.
+
+        Parameters
+        ==========
+
+        force : Expr
+            The scalar expression defining the (expansile) force that the
+            actuator produces.
+        pathway : PathwayBase
+            The pathway that the actuator follows. This must be an instance of
+            a concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``.
+
+        """
+        self.force = force
+        self.pathway = pathway
+
+    @property
+    def force(self):
+        """The magnitude of the force produced by the actuator."""
+        return self._force
+
+    @force.setter
+    def force(self, force):
+        if hasattr(self, '_force'):
+            msg = (
+                f'Can\'t set attribute `force` to {repr(force)} as it is '
+                f'immutable.'
+            )
+            raise AttributeError(msg)
+        self._force = sympify(force, strict=True)
+
+    @property
+    def pathway(self):
+        """The ``Pathway`` defining the actuator's line of action."""
+        return self._pathway
+
+    @pathway.setter
+    def pathway(self, pathway):
+        if hasattr(self, '_pathway'):
+            msg = (
+                f'Can\'t set attribute `pathway` to {repr(pathway)} as it is '
+                f'immutable.'
+            )
+            raise AttributeError(msg)
+        if not isinstance(pathway, PathwayBase):
+            msg = (
+                f'Value {repr(pathway)} passed to `pathway` was of type '
+                f'{type(pathway)}, must be {PathwayBase}.'
+            )
+            raise TypeError(msg)
+        self._pathway = pathway
+
+    def to_loads(self):
+        """Loads required by the equations of motion method classes.
+
+        Explanation
+        ===========
+
+        ``KanesMethod`` requires a list of ``Point``-``Vector`` tuples to be
+        passed to the ``loads`` parameters of its ``kanes_equations`` method
+        when constructing the equations of motion. This method acts as a
+        utility to produce the correctly-structred pairs of points and vectors
+        required so that these can be easily concatenated with other items in
+        the list of loads and passed to ``KanesMethod.kanes_equations``. These
+        loads are also in the correct form to also be passed to the other
+        equations of motion method classes, e.g. ``LagrangesMethod``.
+
+        Examples
+        ========
+
+        The below example shows how to generate the loads produced by a force
+        actuator that follows a linear pathway. In this example we'll assume
+        that the force actuator is being used to model a simple linear spring.
+        First, create a linear pathway between two points separated by the
+        coordinate ``q`` in the ``x`` direction of the global frame ``N``.
+
+        >>> from sympy.physics.mechanics import (LinearPathway, Point,
+        ...     ReferenceFrame)
+        >>> from sympy.physics.vector import dynamicsymbols
+        >>> q = dynamicsymbols('q')
+        >>> N = ReferenceFrame('N')
+        >>> pA, pB = Point('pA'), Point('pB')
+        >>> pB.set_pos(pA, q*N.x)
+        >>> pathway = LinearPathway(pA, pB)
+
+        Now create a symbol ``k`` to describe the spring's stiffness and
+        instantiate a force actuator that produces a (contractile) force
+        proportional to both the spring's stiffness and the pathway's length.
+        Note that actuator classes use the sign convention that expansile
+        forces are positive, so for a spring to produce a contractile force the
+        spring force needs to be calculated as the negative for the stiffness
+        multiplied by the length.
+
+        >>> from sympy import symbols
+        >>> from sympy.physics.mechanics import ForceActuator
+        >>> stiffness = symbols('k')
+        >>> spring_force = -stiffness*pathway.length
+        >>> spring = ForceActuator(spring_force, pathway)
+
+        The forces produced by the spring can be generated in the list of loads
+        form that ``KanesMethod`` (and other equations of motion methods)
+        requires by calling the ``to_loads`` method.
+
+        >>> spring.to_loads()
+        [(pA, k*q(t)*N.x), (pB, - k*q(t)*N.x)]
+
+        A simple linear damper can be modeled in a similar way. Create another
+        symbol ``c`` to describe the dampers damping coefficient. This time
+        instantiate a force actuator that produces a force proportional to both
+        the damper's damping coefficient and the pathway's extension velocity.
+        Note that the damping force is negative as it acts in the opposite
+        direction to which the damper is changing in length.
+
+        >>> damping_coefficient = symbols('c')
+        >>> damping_force = -damping_coefficient*pathway.extension_velocity
+        >>> damper = ForceActuator(damping_force, pathway)
+
+        Again, the forces produces by the damper can be generated by calling
+        the ``to_loads`` method.
+
+        >>> damper.to_loads()
+        [(pA, c*Derivative(q(t), t)*N.x), (pB, - c*Derivative(q(t), t)*N.x)]
+
+        """
+        return self.pathway.to_loads(self.force)
+
+    def __repr__(self):
+        """Representation of a ``ForceActuator``."""
+        return f'{self.__class__.__name__}({self.force}, {self.pathway})'
+
+
+class LinearSpring(ForceActuator):
+    """A spring with its spring force as a linear function of its length.
+
+    Explanation
+    ===========
+
+    Note that the "linear" in the name ``LinearSpring`` refers to the fact that
+    the spring force is a linear function of the springs length. I.e. for a
+    linear spring with stiffness ``k``, distance between its ends of ``x``, and
+    an equilibrium length of ``0``, the spring force will be ``-k*x``, which is
+    a linear function in ``x``. To create a spring that follows a linear, or
+    straight, pathway between its two ends, a ``LinearPathway`` instance needs
+    to be passed to the ``pathway`` parameter.
+
+    A ``LinearSpring`` is a subclass of ``ForceActuator`` and so follows the
+    same sign conventions for length, extension velocity, and the direction of
+    the forces it applies to its points of attachment on bodies. The sign
+    convention for the direction of forces is such that, for the case where a
+    linear spring is instantiated with a ``LinearPathway`` instance as its
+    pathway, they act to push the two ends of the spring away from one another.
+    Because springs produces a contractile force and acts to pull the two ends
+    together towards the equilibrium length when stretched, the scalar portion
+    of the forces on the endpoint are negative in order to flip the sign of the
+    forces on the endpoints when converted into vector quantities. The
+    following diagram shows the positive force sense and the distance between
+    the points::
+
+       P           Q
+       o<--- F --->o
+       |           |
+       |<--l(t)--->|
+
+    Examples
+    ========
+
+    To construct a linear spring, an expression (or symbol) must be supplied to
+    represent the stiffness (spring constant) of the spring, alongside a
+    pathway specifying its line of action. Let's also create a global reference
+    frame and spatially fix one of the points in it while setting the other to
+    be positioned such that it can freely move in the frame's x direction
+    specified by the coordinate ``q``.
+
+    >>> from sympy import symbols
+    >>> from sympy.physics.mechanics import (LinearPathway, LinearSpring,
+    ...     Point, ReferenceFrame)
+    >>> from sympy.physics.vector import dynamicsymbols
+    >>> N = ReferenceFrame('N')
+    >>> q = dynamicsymbols('q')
+    >>> stiffness = symbols('k')
+    >>> pA, pB = Point('pA'), Point('pB')
+    >>> pA.set_vel(N, 0)
+    >>> pB.set_pos(pA, q*N.x)
+    >>> pB.pos_from(pA)
+    q(t)*N.x
+    >>> linear_pathway = LinearPathway(pA, pB)
+    >>> spring = LinearSpring(stiffness, linear_pathway)
+    >>> spring
+    LinearSpring(k, LinearPathway(pA, pB))
+
+    This spring will produce a force that is proportional to both its stiffness
+    and the pathway's length. Note that this force is negative as SymPy's sign
+    convention for actuators is that negative forces are contractile.
+
+    >>> spring.force
+    -k*sqrt(q(t)**2)
+
+    To create a linear spring with a non-zero equilibrium length, an expression
+    (or symbol) can be passed to the ``equilibrium_length`` parameter on
+    construction on a ``LinearSpring`` instance. Let's create a symbol ``l``
+    to denote a non-zero equilibrium length and create another linear spring.
+
+    >>> l = symbols('l')
+    >>> spring = LinearSpring(stiffness, linear_pathway, equilibrium_length=l)
+    >>> spring
+    LinearSpring(k, LinearPathway(pA, pB), equilibrium_length=l)
+
+    The spring force of this new spring is again proportional to both its
+    stiffness and the pathway's length. However, the spring will not produce
+    any force when ``q(t)`` equals ``l``. Note that the force will become
+    expansile when ``q(t)`` is less than ``l``, as expected.
+
+    >>> spring.force
+    -k*(-l + sqrt(q(t)**2))
+
+    Parameters
+    ==========
+
+    stiffness : Expr
+        The spring constant.
+    pathway : PathwayBase
+        The pathway that the actuator follows. This must be an instance of a
+        concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``.
+    equilibrium_length : Expr, optional
+        The length at which the spring is in equilibrium, i.e. it produces no
+        force. The default value is 0, i.e. the spring force is a linear
+        function of the pathway's length with no constant offset.
+
+    See Also
+    ========
+
+    ForceActuator: force-producing actuator (superclass of ``LinearSpring``).
+    LinearPathway: straight-line pathway between a pair of points.
+
+    """
+
+    def __init__(self, stiffness, pathway, equilibrium_length=S.Zero):
+        """Initializer for ``LinearSpring``.
+
+        Parameters
+        ==========
+
+        stiffness : Expr
+            The spring constant.
+        pathway : PathwayBase
+            The pathway that the actuator follows. This must be an instance of
+            a concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``.
+        equilibrium_length : Expr, optional
+            The length at which the spring is in equilibrium, i.e. it produces
+            no force. The default value is 0, i.e. the spring force is a linear
+            function of the pathway's length with no constant offset.
+
+        """
+        self.stiffness = stiffness
+        self.pathway = pathway
+        self.equilibrium_length = equilibrium_length
+
+    @property
+    def force(self):
+        """The spring force produced by the linear spring."""
+        return -self.stiffness*(self.pathway.length - self.equilibrium_length)
+
+    @force.setter
+    def force(self, force):
+        raise AttributeError('Can\'t set computed attribute `force`.')
+
+    @property
+    def stiffness(self):
+        """The spring constant for the linear spring."""
+        return self._stiffness
+
+    @stiffness.setter
+    def stiffness(self, stiffness):
+        if hasattr(self, '_stiffness'):
+            msg = (
+                f'Can\'t set attribute `stiffness` to {repr(stiffness)} as it '
+                f'is immutable.'
+            )
+            raise AttributeError(msg)
+        self._stiffness = sympify(stiffness, strict=True)
+
+    @property
+    def equilibrium_length(self):
+        """The length of the spring at which it produces no force."""
+        return self._equilibrium_length
+
+    @equilibrium_length.setter
+    def equilibrium_length(self, equilibrium_length):
+        if hasattr(self, '_equilibrium_length'):
+            msg = (
+                f'Can\'t set attribute `equilibrium_length` to '
+                f'{repr(equilibrium_length)} as it is immutable.'
+            )
+            raise AttributeError(msg)
+        self._equilibrium_length = sympify(equilibrium_length, strict=True)
+
+    def __repr__(self):
+        """Representation of a ``LinearSpring``."""
+        string = f'{self.__class__.__name__}({self.stiffness}, {self.pathway}'
+        if self.equilibrium_length == S.Zero:
+            string += ')'
+        else:
+            string += f', equilibrium_length={self.equilibrium_length})'
+        return string
+
+
+class LinearDamper(ForceActuator):
+    """A damper whose force is a linear function of its extension velocity.
+
+    Explanation
+    ===========
+
+    Note that the "linear" in the name ``LinearDamper`` refers to the fact that
+    the damping force is a linear function of the damper's rate of change in
+    its length. I.e. for a linear damper with damping ``c`` and extension
+    velocity ``v``, the damping force will be ``-c*v``, which is a linear
+    function in ``v``. To create a damper that follows a linear, or straight,
+    pathway between its two ends, a ``LinearPathway`` instance needs to be
+    passed to the ``pathway`` parameter.
+
+    A ``LinearDamper`` is a subclass of ``ForceActuator`` and so follows the
+    same sign conventions for length, extension velocity, and the direction of
+    the forces it applies to its points of attachment on bodies. The sign
+    convention for the direction of forces is such that, for the case where a
+    linear damper is instantiated with a ``LinearPathway`` instance as its
+    pathway, they act to push the two ends of the damper away from one another.
+    Because dampers produce a force that opposes the direction of change in
+    length, when extension velocity is positive the scalar portions of the
+    forces applied at the two endpoints are negative in order to flip the sign
+    of the forces on the endpoints wen converted into vector quantities. When
+    extension velocity is negative (i.e. when the damper is shortening), the
+    scalar portions of the fofces applied are also negative so that the signs
+    cancel producing forces on the endpoints that are in the same direction as
+    the positive sign convention for the forces at the endpoints of the pathway
+    (i.e. they act to push the endpoints away from one another). The following
+    diagram shows the positive force sense and the distance between the
+    points::
+
+       P           Q
+       o<--- F --->o
+       |           |
+       |<--l(t)--->|
+
+    Examples
+    ========
+
+    To construct a linear damper, an expression (or symbol) must be supplied to
+    represent the damping coefficient of the damper (we'll use the symbol
+    ``c``), alongside a pathway specifying its line of action. Let's also
+    create a global reference frame and spatially fix one of the points in it
+    while setting the other to be positioned such that it can freely move in
+    the frame's x direction specified by the coordinate ``q``. The velocity
+    that the two points move away from one another can be specified by the
+    coordinate ``u`` where ``u`` is the first time derivative of ``q``
+    (i.e., ``u = Derivative(q(t), t)``).
+
+    >>> from sympy import symbols
+    >>> from sympy.physics.mechanics import (LinearDamper, LinearPathway,
+    ...     Point, ReferenceFrame)
+    >>> from sympy.physics.vector import dynamicsymbols
+    >>> N = ReferenceFrame('N')
+    >>> q = dynamicsymbols('q')
+    >>> damping = symbols('c')
+    >>> pA, pB = Point('pA'), Point('pB')
+    >>> pA.set_vel(N, 0)
+    >>> pB.set_pos(pA, q*N.x)
+    >>> pB.pos_from(pA)
+    q(t)*N.x
+    >>> pB.vel(N)
+    Derivative(q(t), t)*N.x
+    >>> linear_pathway = LinearPathway(pA, pB)
+    >>> damper = LinearDamper(damping, linear_pathway)
+    >>> damper
+    LinearDamper(c, LinearPathway(pA, pB))
+
+    This damper will produce a force that is proportional to both its damping
+    coefficient and the pathway's extension length. Note that this force is
+    negative as SymPy's sign convention for actuators is that negative forces
+    are contractile and the damping force of the damper will oppose the
+    direction of length change.
+
+    >>> damper.force
+    -c*sqrt(q(t)**2)*Derivative(q(t), t)/q(t)
+
+    Parameters
+    ==========
+
+    damping : Expr
+        The damping constant.
+    pathway : PathwayBase
+        The pathway that the actuator follows. This must be an instance of a
+        concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``.
+
+    See Also
+    ========
+
+    ForceActuator: force-producing actuator (superclass of ``LinearDamper``).
+    LinearPathway: straight-line pathway between a pair of points.
+
+    """
+
+    def __init__(self, damping, pathway):
+        """Initializer for ``LinearDamper``.
+
+        Parameters
+        ==========
+
+        damping : Expr
+            The damping constant.
+        pathway : PathwayBase
+            The pathway that the actuator follows. This must be an instance of
+            a concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``.
+
+        """
+        self.damping = damping
+        self.pathway = pathway
+
+    @property
+    def force(self):
+        """The damping force produced by the linear damper."""
+        return -self.damping*self.pathway.extension_velocity
+
+    @force.setter
+    def force(self, force):
+        raise AttributeError('Can\'t set computed attribute `force`.')
+
+    @property
+    def damping(self):
+        """The damping constant for the linear damper."""
+        return self._damping
+
+    @damping.setter
+    def damping(self, damping):
+        if hasattr(self, '_damping'):
+            msg = (
+                f'Can\'t set attribute `damping` to {repr(damping)} as it is '
+                f'immutable.'
+            )
+            raise AttributeError(msg)
+        self._damping = sympify(damping, strict=True)
+
+    def __repr__(self):
+        """Representation of a ``LinearDamper``."""
+        return f'{self.__class__.__name__}({self.damping}, {self.pathway})'
+
+
+class TorqueActuator(ActuatorBase):
+    """Torque-producing actuator.
+
+    Explanation
+    ===========
+
+    A ``TorqueActuator`` is an actuator that produces a pair of equal and
+    opposite torques on a pair of bodies.
+
+    Examples
+    ========
+
+    To construct a torque actuator, an expression (or symbol) must be supplied
+    to represent the torque it can produce, alongside a vector specifying the
+    axis about which the torque will act, and a pair of frames on which the
+    torque will act.
+
+    >>> from sympy import symbols
+    >>> from sympy.physics.mechanics import (ReferenceFrame, RigidBody,
+    ...     TorqueActuator)
+    >>> N = ReferenceFrame('N')
+    >>> A = ReferenceFrame('A')
+    >>> torque = symbols('T')
+    >>> axis = N.z
+    >>> parent = RigidBody('parent', frame=N)
+    >>> child = RigidBody('child', frame=A)
+    >>> bodies = (child, parent)
+    >>> actuator = TorqueActuator(torque, axis, *bodies)
+    >>> actuator
+    TorqueActuator(T, axis=N.z, target_frame=A, reaction_frame=N)
+
+    Note that because torques actually act on frames, not bodies,
+    ``TorqueActuator`` will extract the frame associated with a ``RigidBody``
+    when one is passed instead of a ``ReferenceFrame``.
+
+    Parameters
+    ==========
+
+    torque : Expr
+        The scalar expression defining the torque that the actuator produces.
+    axis : Vector
+        The axis about which the actuator applies torques.
+    target_frame : ReferenceFrame | RigidBody
+        The primary frame on which the actuator will apply the torque.
+    reaction_frame : ReferenceFrame | RigidBody | None
+        The secondary frame on which the actuator will apply the torque. Note
+        that the (equal and opposite) reaction torque is applied to this frame.
+
+    """
+
+    def __init__(self, torque, axis, target_frame, reaction_frame=None):
+        """Initializer for ``TorqueActuator``.
+
+        Parameters
+        ==========
+
+        torque : Expr
+            The scalar expression defining the torque that the actuator
+            produces.
+        axis : Vector
+            The axis about which the actuator applies torques.
+        target_frame : ReferenceFrame | RigidBody
+            The primary frame on which the actuator will apply the torque.
+        reaction_frame : ReferenceFrame | RigidBody | None
+           The secondary frame on which the actuator will apply the torque.
+           Note that the (equal and opposite) reaction torque is applied to
+           this frame.
+
+        """
+        self.torque = torque
+        self.axis = axis
+        self.target_frame = target_frame
+        self.reaction_frame = reaction_frame
+
+    @classmethod
+    def at_pin_joint(cls, torque, pin_joint):
+        """Alternate construtor to instantiate from a ``PinJoint`` instance.
+
+        Examples
+        ========
+
+        To create a pin joint the ``PinJoint`` class requires a name, parent
+        body, and child body to be passed to its constructor. It is also
+        possible to control the joint axis using the ``joint_axis`` keyword
+        argument. In this example let's use the parent body's reference frame's
+        z-axis as the joint axis.
+
+        >>> from sympy.physics.mechanics import (PinJoint, ReferenceFrame,
+        ...     RigidBody, TorqueActuator)
+        >>> N = ReferenceFrame('N')
+        >>> A = ReferenceFrame('A')
+        >>> parent = RigidBody('parent', frame=N)
+        >>> child = RigidBody('child', frame=A)
+        >>> pin_joint = PinJoint(
+        ...     'pin',
+        ...     parent,
+        ...     child,
+        ...     joint_axis=N.z,
+        ... )
+
+        Let's also create a symbol ``T`` that will represent the torque applied
+        by the torque actuator.
+
+        >>> from sympy import symbols
+        >>> torque = symbols('T')
+
+        To create the torque actuator from the ``torque`` and ``pin_joint``
+        variables previously instantiated, these can be passed to the alternate
+        constructor class method ``at_pin_joint`` of the ``TorqueActuator``
+        class. It should be noted that a positive torque will cause a positive
+        displacement of the joint coordinate or that the torque is applied on
+        the child body with a reaction torque on the parent.
+
+        >>> actuator = TorqueActuator.at_pin_joint(torque, pin_joint)
+        >>> actuator
+        TorqueActuator(T, axis=N.z, target_frame=A, reaction_frame=N)
+
+        Parameters
+        ==========
+
+        torque : Expr
+            The scalar expression defining the torque that the actuator
+            produces.
+        pin_joint : PinJoint
+            The pin joint, and by association the parent and child bodies, on
+            which the torque actuator will act. The pair of bodies acted upon
+            by the torque actuator are the parent and child bodies of the pin
+            joint, with the child acting as the reaction body. The pin joint's
+            axis is used as the axis about which the torque actuator will apply
+            its torque.
+
+        """
+        if not isinstance(pin_joint, PinJoint):
+            msg = (
+                f'Value {repr(pin_joint)} passed to `pin_joint` was of type '
+                f'{type(pin_joint)}, must be {PinJoint}.'
+            )
+            raise TypeError(msg)
+        return cls(
+            torque,
+            pin_joint.joint_axis,
+            pin_joint.child_interframe,
+            pin_joint.parent_interframe,
+        )
+
+    @property
+    def torque(self):
+        """The magnitude of the torque produced by the actuator."""
+        return self._torque
+
+    @torque.setter
+    def torque(self, torque):
+        if hasattr(self, '_torque'):
+            msg = (
+                f'Can\'t set attribute `torque` to {repr(torque)} as it is '
+                f'immutable.'
+            )
+            raise AttributeError(msg)
+        self._torque = sympify(torque, strict=True)
+
+    @property
+    def axis(self):
+        """The axis about which the torque acts."""
+        return self._axis
+
+    @axis.setter
+    def axis(self, axis):
+        if hasattr(self, '_axis'):
+            msg = (
+                f'Can\'t set attribute `axis` to {repr(axis)} as it is '
+                f'immutable.'
+            )
+            raise AttributeError(msg)
+        if not isinstance(axis, Vector):
+            msg = (
+                f'Value {repr(axis)} passed to `axis` was of type '
+                f'{type(axis)}, must be {Vector}.'
+            )
+            raise TypeError(msg)
+        self._axis = axis
+
+    @property
+    def target_frame(self):
+        """The primary reference frames on which the torque will act."""
+        return self._target_frame
+
+    @target_frame.setter
+    def target_frame(self, target_frame):
+        if hasattr(self, '_target_frame'):
+            msg = (
+                f'Can\'t set attribute `target_frame` to {repr(target_frame)} '
+                f'as it is immutable.'
+            )
+            raise AttributeError(msg)
+        if isinstance(target_frame, RigidBody):
+            target_frame = target_frame.frame
+        elif not isinstance(target_frame, ReferenceFrame):
+            msg = (
+                f'Value {repr(target_frame)} passed to `target_frame` was of '
+                f'type {type(target_frame)}, must be {ReferenceFrame}.'
+            )
+            raise TypeError(msg)
+        self._target_frame = target_frame
+
+    @property
+    def reaction_frame(self):
+        """The primary reference frames on which the torque will act."""
+        return self._reaction_frame
+
+    @reaction_frame.setter
+    def reaction_frame(self, reaction_frame):
+        if hasattr(self, '_reaction_frame'):
+            msg = (
+                f'Can\'t set attribute `reaction_frame` to '
+                f'{repr(reaction_frame)} as it is immutable.'
+            )
+            raise AttributeError(msg)
+        if isinstance(reaction_frame, RigidBody):
+            reaction_frame = reaction_frame.frame
+        elif (
+            not isinstance(reaction_frame, ReferenceFrame)
+            and reaction_frame is not None
+        ):
+            msg = (
+                f'Value {repr(reaction_frame)} passed to `reaction_frame` was '
+                f'of type {type(reaction_frame)}, must be {ReferenceFrame}.'
+            )
+            raise TypeError(msg)
+        self._reaction_frame = reaction_frame
+
+    def to_loads(self):
+        """Loads required by the equations of motion method classes.
+
+        Explanation
+        ===========
+
+        ``KanesMethod`` requires a list of ``Point``-``Vector`` tuples to be
+        passed to the ``loads`` parameters of its ``kanes_equations`` method
+        when constructing the equations of motion. This method acts as a
+        utility to produce the correctly-structred pairs of points and vectors
+        required so that these can be easily concatenated with other items in
+        the list of loads and passed to ``KanesMethod.kanes_equations``. These
+        loads are also in the correct form to also be passed to the other
+        equations of motion method classes, e.g. ``LagrangesMethod``.
+
+        Examples
+        ========
+
+        The below example shows how to generate the loads produced by a torque
+        actuator that acts on a pair of bodies attached by a pin joint.
+
+        >>> from sympy import symbols
+        >>> from sympy.physics.mechanics import (PinJoint, ReferenceFrame,
+        ...     RigidBody, TorqueActuator)
+        >>> torque = symbols('T')
+        >>> N = ReferenceFrame('N')
+        >>> A = ReferenceFrame('A')
+        >>> parent = RigidBody('parent', frame=N)
+        >>> child = RigidBody('child', frame=A)
+        >>> pin_joint = PinJoint(
+        ...     'pin',
+        ...     parent,
+        ...     child,
+        ...     joint_axis=N.z,
+        ... )
+        >>> actuator = TorqueActuator.at_pin_joint(torque, pin_joint)
+
+        The forces produces by the damper can be generated by calling the
+        ``to_loads`` method.
+
+        >>> actuator.to_loads()
+        [(A, T*N.z), (N, - T*N.z)]
+
+        Alternatively, if a torque actuator is created without a reaction frame
+        then the loads returned by the ``to_loads`` method will contain just
+        the single load acting on the target frame.
+
+        >>> actuator = TorqueActuator(torque, N.z, N)
+        >>> actuator.to_loads()
+        [(N, T*N.z)]
+
+        """
+        loads = [
+            Torque(self.target_frame, self.torque*self.axis),
+        ]
+        if self.reaction_frame is not None:
+            loads.append(Torque(self.reaction_frame, -self.torque*self.axis))
+        return loads
+
+    def __repr__(self):
+        """Representation of a ``TorqueActuator``."""
+        string = (
+            f'{self.__class__.__name__}({self.torque}, axis={self.axis}, '
+            f'target_frame={self.target_frame}'
+        )
+        if self.reaction_frame is not None:
+            string += f', reaction_frame={self.reaction_frame})'
+        else:
+            string += ')'
+        return string
+
+
+class DuffingSpring(ForceActuator):
+    """A nonlinear spring based on the Duffing equation.
+
+    Explanation
+    ===========
+
+    Here, ``DuffingSpring`` represents the force exerted by a nonlinear spring based on the Duffing equation:
+    F = -beta*x-alpha*x**3, where x is the displacement from the equilibrium position, beta is the linear spring constant,
+    and alpha is the coefficient for the nonlinear cubic term.
+
+    Parameters
+    ==========
+
+    linear_stiffness : Expr
+        The linear stiffness coefficient (beta).
+    nonlinear_stiffness : Expr
+        The nonlinear stiffness coefficient (alpha).
+    pathway : PathwayBase
+        The pathway that the actuator follows.
+    equilibrium_length : Expr, optional
+        The length at which the spring is in equilibrium (x).
+    """
+
+    def __init__(self, linear_stiffness, nonlinear_stiffness, pathway, equilibrium_length=S.Zero):
+        self.linear_stiffness = sympify(linear_stiffness, strict=True)
+        self.nonlinear_stiffness = sympify(nonlinear_stiffness, strict=True)
+        self.equilibrium_length = sympify(equilibrium_length, strict=True)
+
+        if not isinstance(pathway, PathwayBase):
+            raise TypeError("pathway must be an instance of PathwayBase.")
+        self._pathway = pathway
+
+    @property
+    def linear_stiffness(self):
+        return self._linear_stiffness
+
+    @linear_stiffness.setter
+    def linear_stiffness(self, linear_stiffness):
+        if hasattr(self, '_linear_stiffness'):
+            msg = (
+                f'Can\'t set attribute `linear_stiffness` to '
+                f'{repr(linear_stiffness)} as it is immutable.'
+            )
+            raise AttributeError(msg)
+        self._linear_stiffness = sympify(linear_stiffness, strict=True)
+
+    @property
+    def nonlinear_stiffness(self):
+        return self._nonlinear_stiffness
+
+    @nonlinear_stiffness.setter
+    def nonlinear_stiffness(self, nonlinear_stiffness):
+        if hasattr(self, '_nonlinear_stiffness'):
+            msg = (
+                f'Can\'t set attribute `nonlinear_stiffness` to '
+                f'{repr(nonlinear_stiffness)} as it is immutable.'
+            )
+            raise AttributeError(msg)
+        self._nonlinear_stiffness = sympify(nonlinear_stiffness, strict=True)
+
+    @property
+    def pathway(self):
+        return self._pathway
+
+    @pathway.setter
+    def pathway(self, pathway):
+        if hasattr(self, '_pathway'):
+            msg = (
+                f'Can\'t set attribute `pathway` to {repr(pathway)} as it is '
+                f'immutable.'
+            )
+            raise AttributeError(msg)
+        if not isinstance(pathway, PathwayBase):
+            msg = (
+                f'Value {repr(pathway)} passed to `pathway` was of type '
+                f'{type(pathway)}, must be {PathwayBase}.'
+            )
+            raise TypeError(msg)
+        self._pathway = pathway
+
+    @property
+    def equilibrium_length(self):
+        return self._equilibrium_length
+
+    @equilibrium_length.setter
+    def equilibrium_length(self, equilibrium_length):
+        if hasattr(self, '_equilibrium_length'):
+            msg = (
+                f'Can\'t set attribute `equilibrium_length` to '
+                f'{repr(equilibrium_length)} as it is immutable.'
+            )
+            raise AttributeError(msg)
+        self._equilibrium_length = sympify(equilibrium_length, strict=True)
+
+    @property
+    def force(self):
+        """The force produced by the Duffing spring."""
+        displacement = self.pathway.length - self.equilibrium_length
+        return -self.linear_stiffness * displacement - self.nonlinear_stiffness * displacement**3
+
+    @force.setter
+    def force(self, force):
+        if hasattr(self, '_force'):
+            msg = (
+                f'Can\'t set attribute `force` to {repr(force)} as it is '
+                f'immutable.'
+            )
+            raise AttributeError(msg)
+        self._force = sympify(force, strict=True)
+
+    def __repr__(self):
+        return (f"{self.__class__.__name__}("
+                f"{self.linear_stiffness}, {self.nonlinear_stiffness}, {self.pathway}, "
+                f"equilibrium_length={self.equilibrium_length})")

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/inertia.py

@@ -0,0 +1,197 @@
+from sympy import sympify
+from sympy.physics.vector import Point, Dyadic, ReferenceFrame, outer
+from collections import namedtuple
+
+__all__ = ['inertia', 'inertia_of_point_mass', 'Inertia']
+
+
+def inertia(frame, ixx, iyy, izz, ixy=0, iyz=0, izx=0):
+    """Simple way to create inertia Dyadic object.
+
+    Explanation
+    ===========
+
+    Creates an inertia Dyadic based on the given tensor values and a body-fixed
+    reference frame.
+
+    Parameters
+    ==========
+
+    frame : ReferenceFrame
+        The frame the inertia is defined in.
+    ixx : Sympifyable
+        The xx element in the inertia dyadic.
+    iyy : Sympifyable
+        The yy element in the inertia dyadic.
+    izz : Sympifyable
+        The zz element in the inertia dyadic.
+    ixy : Sympifyable
+        The xy element in the inertia dyadic.
+    iyz : Sympifyable
+        The yz element in the inertia dyadic.
+    izx : Sympifyable
+        The zx element in the inertia dyadic.
+
+    Examples
+    ========
+
+    >>> from sympy.physics.mechanics import ReferenceFrame, inertia
+    >>> N = ReferenceFrame('N')
+    >>> inertia(N, 1, 2, 3)
+    (N.x|N.x) + 2*(N.y|N.y) + 3*(N.z|N.z)
+
+    """
+
+    if not isinstance(frame, ReferenceFrame):
+        raise TypeError('Need to define the inertia in a frame')
+    ixx, iyy, izz = sympify(ixx), sympify(iyy), sympify(izz)
+    ixy, iyz, izx = sympify(ixy), sympify(iyz), sympify(izx)
+    return (ixx*outer(frame.x, frame.x) + ixy*outer(frame.x, frame.y) +
+            izx*outer(frame.x, frame.z) + ixy*outer(frame.y, frame.x) +
+            iyy*outer(frame.y, frame.y) + iyz*outer(frame.y, frame.z) +
+            izx*outer(frame.z, frame.x) + iyz*outer(frame.z, frame.y) +
+            izz*outer(frame.z, frame.z))
+
+
+def inertia_of_point_mass(mass, pos_vec, frame):
+    """Inertia dyadic of a point mass relative to point O.
+
+    Parameters
+    ==========
+
+    mass : Sympifyable
+        Mass of the point mass
+    pos_vec : Vector
+        Position from point O to point mass
+    frame : ReferenceFrame
+        Reference frame to express the dyadic in
+
+    Examples
+    ========
+
+    >>> from sympy import symbols
+    >>> from sympy.physics.mechanics import ReferenceFrame, inertia_of_point_mass
+    >>> N = ReferenceFrame('N')
+    >>> r, m = symbols('r m')
+    >>> px = r * N.x
+    >>> inertia_of_point_mass(m, px, N)
+    m*r**2*(N.y|N.y) + m*r**2*(N.z|N.z)
+
+    """
+
+    return mass*(
+        (outer(frame.x, frame.x) +
+         outer(frame.y, frame.y) +
+         outer(frame.z, frame.z)) *
+        (pos_vec.dot(pos_vec)) - outer(pos_vec, pos_vec))
+
+
+class Inertia(namedtuple('Inertia', ['dyadic', 'point'])):
+    """Inertia object consisting of a Dyadic and a Point of reference.
+
+    Explanation
+    ===========
+
+    This is a simple class to store the Point and Dyadic, belonging to an
+    inertia.
+
+    Attributes
+    ==========
+
+    dyadic : Dyadic
+        The dyadic of the inertia.
+    point : Point
+        The reference point of the inertia.
+
+    Examples
+    ========
+
+    >>> from sympy.physics.mechanics import ReferenceFrame, Point, Inertia
+    >>> N = ReferenceFrame('N')
+    >>> Po = Point('Po')
+    >>> Inertia(N.x.outer(N.x) + N.y.outer(N.y) + N.z.outer(N.z), Po)
+    ((N.x|N.x) + (N.y|N.y) + (N.z|N.z), Po)
+
+    In the example above the Dyadic was created manually, one can however also
+    use the ``inertia`` function for this or the class method ``from_tensor`` as
+    shown below.
+
+    >>> Inertia.from_inertia_scalars(Po, N, 1, 1, 1)
+    ((N.x|N.x) + (N.y|N.y) + (N.z|N.z), Po)
+
+    """
+    def __new__(cls, dyadic, point):
+        # Switch order if given in the wrong order
+        if isinstance(dyadic, Point) and isinstance(point, Dyadic):
+            point, dyadic = dyadic, point
+        if not isinstance(point, Point):
+            raise TypeError('Reference point should be of type Point')
+        if not isinstance(dyadic, Dyadic):
+            raise TypeError('Inertia value should be expressed as a Dyadic')
+        return super().__new__(cls, dyadic, point)
+
+    @classmethod
+    def from_inertia_scalars(cls, point, frame, ixx, iyy, izz, ixy=0, iyz=0,
+                             izx=0):
+        """Simple way to create an Inertia object based on the tensor values.
+
+        Explanation
+        ===========
+
+        This class method uses the :func`~.inertia` to create the Dyadic based
+        on the tensor values.
+
+        Parameters
+        ==========
+
+        point : Point
+            The reference point of the inertia.
+        frame : ReferenceFrame
+            The frame the inertia is defined in.
+        ixx : Sympifyable
+            The xx element in the inertia dyadic.
+        iyy : Sympifyable
+            The yy element in the inertia dyadic.
+        izz : Sympifyable
+            The zz element in the inertia dyadic.
+        ixy : Sympifyable
+            The xy element in the inertia dyadic.
+        iyz : Sympifyable
+            The yz element in the inertia dyadic.
+        izx : Sympifyable
+            The zx element in the inertia dyadic.
+
+        Examples
+        ========
+
+        >>> from sympy import symbols
+        >>> from sympy.physics.mechanics import ReferenceFrame, Point, Inertia
+        >>> ixx, iyy, izz, ixy, iyz, izx = symbols('ixx iyy izz ixy iyz izx')
+        >>> N = ReferenceFrame('N')
+        >>> P = Point('P')
+        >>> I = Inertia.from_inertia_scalars(P, N, ixx, iyy, izz, ixy, iyz, izx)
+
+        The tensor values can easily be seen when converting the dyadic to a
+        matrix.
+
+        >>> I.dyadic.to_matrix(N)
+        Matrix([
+        [ixx, ixy, izx],
+        [ixy, iyy, iyz],
+        [izx, iyz, izz]])
+
+        """
+        return cls(inertia(frame, ixx, iyy, izz, ixy, iyz, izx), point)
+
+    def __add__(self, other):
+        raise TypeError(f"unsupported operand type(s) for +: "
+                        f"'{self.__class__.__name__}' and "
+                        f"'{other.__class__.__name__}'")
+
+    def __mul__(self, other):
+        raise TypeError(f"unsupported operand type(s) for *: "
+                        f"'{self.__class__.__name__}' and "
+                        f"'{other.__class__.__name__}'")
+
+    __radd__ = __add__
+    __rmul__ = __mul__

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/joint.py

@@ -0,0 +1,2188 @@
+# coding=utf-8
+
+from abc import ABC, abstractmethod
+
+from sympy import pi, Derivative, Matrix
+from sympy.core.function import AppliedUndef
+from sympy.physics.mechanics.body_base import BodyBase
+from sympy.physics.mechanics.functions import _validate_coordinates
+from sympy.physics.vector import (Vector, dynamicsymbols, cross, Point,
+                                  ReferenceFrame)
+from sympy.utilities.iterables import iterable
+from sympy.utilities.exceptions import sympy_deprecation_warning
+
+__all__ = ['Joint', 'PinJoint', 'PrismaticJoint', 'CylindricalJoint',
+           'PlanarJoint', 'SphericalJoint', 'WeldJoint']
+
+
+class Joint(ABC):
+    """Abstract base class for all specific joints.
+
+    Explanation
+    ===========
+
+    A joint subtracts degrees of freedom from a body. This is the base class
+    for all specific joints and holds all common methods acting as an interface
+    for all joints. Custom joint can be created by inheriting Joint class and
+    defining all abstract functions.
+
+    The abstract methods are:
+
+    - ``_generate_coordinates``
+    - ``_generate_speeds``
+    - ``_orient_frames``
+    - ``_set_angular_velocity``
+    - ``_set_linear_velocity``
+
+    Parameters
+    ==========
+
+    name : string
+        A unique name for the joint.
+    parent : Particle or RigidBody or Body
+        The parent body of joint.
+    child : Particle or RigidBody or Body
+        The child body of joint.
+    coordinates : iterable of dynamicsymbols, optional
+        Generalized coordinates of the joint.
+    speeds : iterable of dynamicsymbols, optional
+        Generalized speeds of joint.
+    parent_point : Point or Vector, optional
+        Attachment point where the joint is fixed to the parent body. If a
+        vector is provided, then the attachment point is computed by adding the
+        vector to the body's mass center. The default value is the parent's mass
+        center.
+    child_point : Point or Vector, optional
+        Attachment point where the joint is fixed to the child body. If a
+        vector is provided, then the attachment point is computed by adding the
+        vector to the body's mass center. The default value is the child's mass
+        center.
+    parent_axis : Vector, optional
+        .. deprecated:: 1.12
+            Axis fixed in the parent body which aligns with an axis fixed in the
+            child body. The default is the x axis of parent's reference frame.
+            For more information on this deprecation, see
+            :ref:`deprecated-mechanics-joint-axis`.
+    child_axis : Vector, optional
+        .. deprecated:: 1.12
+            Axis fixed in the child body which aligns with an axis fixed in the
+            parent body. The default is the x axis of child's reference frame.
+            For more information on this deprecation, see
+            :ref:`deprecated-mechanics-joint-axis`.
+    parent_interframe : ReferenceFrame, optional
+        Intermediate frame of the parent body with respect to which the joint
+        transformation is formulated. If a Vector is provided then an interframe
+        is created which aligns its X axis with the given vector. The default
+        value is the parent's own frame.
+    child_interframe : ReferenceFrame, optional
+        Intermediate frame of the child body with respect to which the joint
+        transformation is formulated. If a Vector is provided then an interframe
+        is created which aligns its X axis with the given vector. The default
+        value is the child's own frame.
+    parent_joint_pos : Point or Vector, optional
+        .. deprecated:: 1.12
+            This argument is replaced by parent_point and will be removed in a
+            future version.
+            See :ref:`deprecated-mechanics-joint-pos` for more information.
+    child_joint_pos : Point or Vector, optional
+        .. deprecated:: 1.12
+            This argument is replaced by child_point and will be removed in a
+            future version.
+            See :ref:`deprecated-mechanics-joint-pos` for more information.
+
+    Attributes
+    ==========
+
+    name : string
+        The joint's name.
+    parent : Particle or RigidBody or Body
+        The joint's parent body.
+    child : Particle or RigidBody or Body
+        The joint's child body.
+    coordinates : Matrix
+        Matrix of the joint's generalized coordinates.
+    speeds : Matrix
+        Matrix of the joint's generalized speeds.
+    parent_point : Point
+        Attachment point where the joint is fixed to the parent body.
+    child_point : Point
+        Attachment point where the joint is fixed to the child body.
+    parent_axis : Vector
+        The axis fixed in the parent frame that represents the joint.
+    child_axis : Vector
+        The axis fixed in the child frame that represents the joint.
+    parent_interframe : ReferenceFrame
+        Intermediate frame of the parent body with respect to which the joint
+        transformation is formulated.
+    child_interframe : ReferenceFrame
+        Intermediate frame of the child body with respect to which the joint
+        transformation is formulated.
+    kdes : Matrix
+        Kinematical differential equations of the joint.
+
+    Notes
+    =====
+
+    When providing a vector as the intermediate frame, a new intermediate frame
+    is created which aligns its X axis with the provided vector. This is done
+    with a single fixed rotation about a rotation axis. This rotation axis is
+    determined by taking the cross product of the ``body.x`` axis with the
+    provided vector. In the case where the provided vector is in the ``-body.x``
+    direction, the rotation is done about the ``body.y`` axis.
+
+    """
+
+    def __init__(self, name, parent, child, coordinates=None, speeds=None,
+                 parent_point=None, child_point=None, parent_interframe=None,
+                 child_interframe=None, parent_axis=None, child_axis=None,
+                 parent_joint_pos=None, child_joint_pos=None):
+
+        if not isinstance(name, str):
+            raise TypeError('Supply a valid name.')
+        self._name = name
+
+        if not isinstance(parent, BodyBase):
+            raise TypeError('Parent must be a body.')
+        self._parent = parent
+
+        if not isinstance(child, BodyBase):
+            raise TypeError('Child must be a body.')
+        self._child = child
+
+        if parent_axis is not None or child_axis is not None:
+            sympy_deprecation_warning(
+                """
+                The parent_axis and child_axis arguments for the Joint classes
+                are deprecated. Instead use parent_interframe, child_interframe.
+                """,
+                deprecated_since_version="1.12",
+                active_deprecations_target="deprecated-mechanics-joint-axis",
+                stacklevel=4
+            )
+            if parent_interframe is None:
+                parent_interframe = parent_axis
+            if child_interframe is None:
+                child_interframe = child_axis
+
+        # Set parent and child frame attributes
+        if hasattr(self._parent, 'frame'):
+            self._parent_frame = self._parent.frame
+        else:
+            if isinstance(parent_interframe, ReferenceFrame):
+                self._parent_frame = parent_interframe
+            else:
+                self._parent_frame = ReferenceFrame(
+                    f'{self.name}_{self._parent.name}_frame')
+        if hasattr(self._child, 'frame'):
+            self._child_frame = self._child.frame
+        else:
+            if isinstance(child_interframe, ReferenceFrame):
+                self._child_frame = child_interframe
+            else:
+                self._child_frame = ReferenceFrame(
+                    f'{self.name}_{self._child.name}_frame')
+
+        self._parent_interframe = self._locate_joint_frame(
+            self._parent, parent_interframe, self._parent_frame)
+        self._child_interframe = self._locate_joint_frame(
+            self._child, child_interframe, self._child_frame)
+        self._parent_axis = self._axis(parent_axis, self._parent_frame)
+        self._child_axis = self._axis(child_axis, self._child_frame)
+
+        if parent_joint_pos is not None or child_joint_pos is not None:
+            sympy_deprecation_warning(
+                """
+                The parent_joint_pos and child_joint_pos arguments for the Joint
+                classes are deprecated. Instead use parent_point and child_point.
+                """,
+                deprecated_since_version="1.12",
+                active_deprecations_target="deprecated-mechanics-joint-pos",
+                stacklevel=4
+            )
+            if parent_point is None:
+                parent_point = parent_joint_pos
+            if child_point is None:
+                child_point = child_joint_pos
+        self._parent_point = self._locate_joint_pos(
+            self._parent, parent_point, self._parent_frame)
+        self._child_point = self._locate_joint_pos(
+            self._child, child_point, self._child_frame)
+
+        self._coordinates = self._generate_coordinates(coordinates)
+        self._speeds = self._generate_speeds(speeds)
+        _validate_coordinates(self.coordinates, self.speeds)
+        self._kdes = self._generate_kdes()
+
+        self._orient_frames()
+        self._set_angular_velocity()
+        self._set_linear_velocity()
+
+    def __str__(self):
+        return self.name
+
+    def __repr__(self):
+        return self.__str__()
+
+    @property
+    def name(self):
+        """Name of the joint."""
+        return self._name
+
+    @property
+    def parent(self):
+        """Parent body of Joint."""
+        return self._parent
+
+    @property
+    def child(self):
+        """Child body of Joint."""
+        return self._child
+
+    @property
+    def coordinates(self):
+        """Matrix of the joint's generalized coordinates."""
+        return self._coordinates
+
+    @property
+    def speeds(self):
+        """Matrix of the joint's generalized speeds."""
+        return self._speeds
+
+    @property
+    def kdes(self):
+        """Kinematical differential equations of the joint."""
+        return self._kdes
+
+    @property
+    def parent_axis(self):
+        """The axis of parent frame."""
+        # Will be removed with `deprecated-mechanics-joint-axis`
+        return self._parent_axis
+
+    @property
+    def child_axis(self):
+        """The axis of child frame."""
+        # Will be removed with `deprecated-mechanics-joint-axis`
+        return self._child_axis
+
+    @property
+    def parent_point(self):
+        """Attachment point where the joint is fixed to the parent body."""
+        return self._parent_point
+
+    @property
+    def child_point(self):
+        """Attachment point where the joint is fixed to the child body."""
+        return self._child_point
+
+    @property
+    def parent_interframe(self):
+        return self._parent_interframe
+
+    @property
+    def child_interframe(self):
+        return self._child_interframe
+
+    @abstractmethod
+    def _generate_coordinates(self, coordinates):
+        """Generate Matrix of the joint's generalized coordinates."""
+        pass
+
+    @abstractmethod
+    def _generate_speeds(self, speeds):
+        """Generate Matrix of the joint's generalized speeds."""
+        pass
+
+    @abstractmethod
+    def _orient_frames(self):
+        """Orient frames as per the joint."""
+        pass
+
+    @abstractmethod
+    def _set_angular_velocity(self):
+        """Set angular velocity of the joint related frames."""
+        pass
+
+    @abstractmethod
+    def _set_linear_velocity(self):
+        """Set velocity of related points to the joint."""
+        pass
+
+    @staticmethod
+    def _to_vector(matrix, frame):
+        """Converts a matrix to a vector in the given frame."""
+        return Vector([(matrix, frame)])
+
+    @staticmethod
+    def _axis(ax, *frames):
+        """Check whether an axis is fixed in one of the frames."""
+        if ax is None:
+            ax = frames[0].x
+            return ax
+        if not isinstance(ax, Vector):
+            raise TypeError("Axis must be a Vector.")
+        ref_frame = None  # Find a body in which the axis can be expressed
+        for frame in frames:
+            try:
+                ax.to_matrix(frame)
+            except ValueError:
+                pass
+            else:
+                ref_frame = frame
+                break
+        if ref_frame is None:
+            raise ValueError("Axis cannot be expressed in one of the body's "
+                             "frames.")
+        if not ax.dt(ref_frame) == 0:
+            raise ValueError('Axis cannot be time-varying when viewed from the '
+                             'associated body.')
+        return ax
+
+    @staticmethod
+    def _choose_rotation_axis(frame, axis):
+        components = axis.to_matrix(frame)
+        x, y, z = components[0], components[1], components[2]
+
+        if x != 0:
+            if y != 0:
+                if z != 0:
+                    return cross(axis, frame.x)
+            if z != 0:
+                return frame.y
+            return frame.z
+        else:
+            if y != 0:
+                return frame.x
+            return frame.y
+
+    @staticmethod
+    def _create_aligned_interframe(frame, align_axis, frame_axis=None,
+                                   frame_name=None):
+        """
+        Returns an intermediate frame, where the ``frame_axis`` defined in
+        ``frame`` is aligned with ``axis``. By default this means that the X
+        axis will be aligned with ``axis``.
+
+        Parameters
+        ==========
+
+        frame : BodyBase or ReferenceFrame
+            The body or reference frame with respect to which the intermediate
+            frame is oriented.
+        align_axis : Vector
+            The vector with respect to which the intermediate frame will be
+            aligned.
+        frame_axis : Vector
+            The vector of the frame which should get aligned with ``axis``. The
+            default is the X axis of the frame.
+        frame_name : string
+            Name of the to be created intermediate frame. The default adds
+            "_int_frame" to the name of ``frame``.
+
+        Example
+        =======
+
+        An intermediate frame, where the X axis of the parent becomes aligned
+        with ``parent.y + parent.z`` can be created as follows:
+
+        >>> from sympy.physics.mechanics.joint import Joint
+        >>> from sympy.physics.mechanics import RigidBody
+        >>> parent = RigidBody('parent')
+        >>> parent_interframe = Joint._create_aligned_interframe(
+        ...     parent, parent.y + parent.z)
+        >>> parent_interframe
+        parent_int_frame
+        >>> parent.frame.dcm(parent_interframe)
+        Matrix([
+        [        0, -sqrt(2)/2, -sqrt(2)/2],
+        [sqrt(2)/2,        1/2,       -1/2],
+        [sqrt(2)/2,       -1/2,        1/2]])
+        >>> (parent.y + parent.z).express(parent_interframe)
+        sqrt(2)*parent_int_frame.x
+
+        Notes
+        =====
+
+        The direction cosine matrix between the given frame and intermediate
+        frame is formed using a simple rotation about an axis that is normal to
+        both ``align_axis`` and ``frame_axis``. In general, the normal axis is
+        formed by crossing the ``frame_axis`` with the ``align_axis``. The
+        exception is if the axes are parallel with opposite directions, in which
+        case the rotation vector is chosen using the rules in the following
+        table with the vectors expressed in the given frame:
+
+        .. list-table::
+           :header-rows: 1
+
+           * - ``align_axis``
+             - ``frame_axis``
+             - ``rotation_axis``
+           * - ``-x``
+             - ``x``
+             - ``z``
+           * - ``-y``
+             - ``y``
+             - ``x``
+           * - ``-z``
+             - ``z``
+             - ``y``
+           * - ``-x-y``
+             - ``x+y``
+             - ``z``
+           * - ``-y-z``
+             - ``y+z``
+             - ``x``
+           * - ``-x-z``
+             - ``x+z``
+             - ``y``
+           * - ``-x-y-z``
+             - ``x+y+z``
+             - ``(x+y+z) × x``
+
+        """
+        if isinstance(frame, BodyBase):
+            frame = frame.frame
+        if frame_axis is None:
+            frame_axis = frame.x
+        if frame_name is None:
+            if frame.name[-6:] == '_frame':
+                frame_name = f'{frame.name[:-6]}_int_frame'
+            else:
+                frame_name = f'{frame.name}_int_frame'
+        angle = frame_axis.angle_between(align_axis)
+        rotation_axis = cross(frame_axis, align_axis)
+        if rotation_axis == Vector(0) and angle == 0:
+            return frame
+        if angle == pi:
+            rotation_axis = Joint._choose_rotation_axis(frame, align_axis)
+
+        int_frame = ReferenceFrame(frame_name)
+        int_frame.orient_axis(frame, rotation_axis, angle)
+        int_frame.set_ang_vel(frame, 0 * rotation_axis)
+        return int_frame
+
+    def _generate_kdes(self):
+        """Generate kinematical differential equations."""
+        kdes = []
+        t = dynamicsymbols._t
+        for i in range(len(self.coordinates)):
+            kdes.append(-self.coordinates[i].diff(t) + self.speeds[i])
+        return Matrix(kdes)
+
+    def _locate_joint_pos(self, body, joint_pos, body_frame=None):
+        """Returns the attachment point of a body."""
+        if body_frame is None:
+            body_frame = body.frame
+        if joint_pos is None:
+            return body.masscenter
+        if not isinstance(joint_pos, (Point, Vector)):
+            raise TypeError('Attachment point must be a Point or Vector.')
+        if isinstance(joint_pos, Vector):
+            point_name = f'{self.name}_{body.name}_joint'
+            joint_pos = body.masscenter.locatenew(point_name, joint_pos)
+        if not joint_pos.pos_from(body.masscenter).dt(body_frame) == 0:
+            raise ValueError('Attachment point must be fixed to the associated '
+                             'body.')
+        return joint_pos
+
+    def _locate_joint_frame(self, body, interframe, body_frame=None):
+        """Returns the attachment frame of a body."""
+        if body_frame is None:
+            body_frame = body.frame
+        if interframe is None:
+            return body_frame
+        if isinstance(interframe, Vector):
+            interframe = Joint._create_aligned_interframe(
+                body_frame, interframe,
+                frame_name=f'{self.name}_{body.name}_int_frame')
+        elif not isinstance(interframe, ReferenceFrame):
+            raise TypeError('Interframe must be a ReferenceFrame.')
+        if not interframe.ang_vel_in(body_frame) == 0:
+            raise ValueError(f'Interframe {interframe} is not fixed to body '
+                             f'{body}.')
+        body.masscenter.set_vel(interframe, 0)  # Fixate interframe to body
+        return interframe
+
+    def _fill_coordinate_list(self, coordinates, n_coords, label='q', offset=0,
+                              number_single=False):
+        """Helper method for _generate_coordinates and _generate_speeds.
+
+        Parameters
+        ==========
+
+        coordinates : iterable
+            Iterable of coordinates or speeds that have been provided.
+        n_coords : Integer
+            Number of coordinates that should be returned.
+        label : String, optional
+            Coordinate type either 'q' (coordinates) or 'u' (speeds). The
+            Default is 'q'.
+        offset : Integer
+            Count offset when creating new dynamicsymbols. The default is 0.
+        number_single : Boolean
+            Boolean whether if n_coords == 1, number should still be used. The
+            default is False.
+
+        """
+
+        def create_symbol(number):
+            if n_coords == 1 and not number_single:
+                return dynamicsymbols(f'{label}_{self.name}')
+            return dynamicsymbols(f'{label}{number}_{self.name}')
+
+        name = 'generalized coordinate' if label == 'q' else 'generalized speed'
+        generated_coordinates = []
+        if coordinates is None:
+            coordinates = []
+        elif not iterable(coordinates):
+            coordinates = [coordinates]
+        if not (len(coordinates) == 0 or len(coordinates) == n_coords):
+            raise ValueError(f'Expected {n_coords} {name}s, instead got '
+                             f'{len(coordinates)} {name}s.')
+        # Supports more iterables, also Matrix
+        for i, coord in enumerate(coordinates):
+            if coord is None:
+                generated_coordinates.append(create_symbol(i + offset))
+            elif isinstance(coord, (AppliedUndef, Derivative)):
+                generated_coordinates.append(coord)
+            else:
+                raise TypeError(f'The {name} {coord} should have been a '
+                                f'dynamicsymbol.')
+        for i in range(len(coordinates) + offset, n_coords + offset):
+            generated_coordinates.append(create_symbol(i))
+        return Matrix(generated_coordinates)
+
+
+class PinJoint(Joint):
+    """Pin (Revolute) Joint.
+
+    .. raw:: html
+        :file: ../../../doc/src/modules/physics/mechanics/api/PinJoint.svg
+
+    Explanation
+    ===========
+
+    A pin joint is defined such that the joint rotation axis is fixed in both
+    the child and parent and the location of the joint is relative to the mass
+    center of each body. The child rotates an angle, θ, from the parent about
+    the rotation axis and has a simple angular speed, ω, relative to the
+    parent. The direction cosine matrix between the child interframe and
+    parent interframe is formed using a simple rotation about the joint axis.
+    The page on the joints framework gives a more detailed explanation of the
+    intermediate frames.
+
+    Parameters
+    ==========
+
+    name : string
+        A unique name for the joint.
+    parent : Particle or RigidBody or Body
+        The parent body of joint.
+    child : Particle or RigidBody or Body
+        The child body of joint.
+    coordinates : dynamicsymbol, optional
+        Generalized coordinates of the joint.
+    speeds : dynamicsymbol, optional
+        Generalized speeds of joint.
+    parent_point : Point or Vector, optional
+        Attachment point where the joint is fixed to the parent body. If a
+        vector is provided, then the attachment point is computed by adding the
+        vector to the body's mass center. The default value is the parent's mass
+        center.
+    child_point : Point or Vector, optional
+        Attachment point where the joint is fixed to the child body. If a
+        vector is provided, then the attachment point is computed by adding the
+        vector to the body's mass center. The default value is the child's mass
+        center.
+    parent_axis : Vector, optional
+        .. deprecated:: 1.12
+            Axis fixed in the parent body which aligns with an axis fixed in the
+            child body. The default is the x axis of parent's reference frame.
+            For more information on this deprecation, see
+            :ref:`deprecated-mechanics-joint-axis`.
+    child_axis : Vector, optional
+        .. deprecated:: 1.12
+            Axis fixed in the child body which aligns with an axis fixed in the
+            parent body. The default is the x axis of child's reference frame.
+            For more information on this deprecation, see
+            :ref:`deprecated-mechanics-joint-axis`.
+    parent_interframe : ReferenceFrame, optional
+        Intermediate frame of the parent body with respect to which the joint
+        transformation is formulated. If a Vector is provided then an interframe
+        is created which aligns its X axis with the given vector. The default
+        value is the parent's own frame.
+    child_interframe : ReferenceFrame, optional
+        Intermediate frame of the child body with respect to which the joint
+        transformation is formulated. If a Vector is provided then an interframe
+        is created which aligns its X axis with the given vector. The default
+        value is the child's own frame.
+    joint_axis : Vector
+        The axis about which the rotation occurs. Note that the components
+        of this axis are the same in the parent_interframe and child_interframe.
+    parent_joint_pos : Point or Vector, optional
+        .. deprecated:: 1.12
+            This argument is replaced by parent_point and will be removed in a
+            future version.
+            See :ref:`deprecated-mechanics-joint-pos` for more information.
+    child_joint_pos : Point or Vector, optional
+        .. deprecated:: 1.12
+            This argument is replaced by child_point and will be removed in a
+            future version.
+            See :ref:`deprecated-mechanics-joint-pos` for more information.
+
+    Attributes
+    ==========
+
+    name : string
+        The joint's name.
+    parent : Particle or RigidBody or Body
+        The joint's parent body.
+    child : Particle or RigidBody or Body
+        The joint's child body.
+    coordinates : Matrix
+        Matrix of the joint's generalized coordinates. The default value is
+        ``dynamicsymbols(f'q_{joint.name}')``.
+    speeds : Matrix
+        Matrix of the joint's generalized speeds. The default value is
+        ``dynamicsymbols(f'u_{joint.name}')``.
+    parent_point : Point
+        Attachment point where the joint is fixed to the parent body.
+    child_point : Point
+        Attachment point where the joint is fixed to the child body.
+    parent_axis : Vector
+        The axis fixed in the parent frame that represents the joint.
+    child_axis : Vector
+        The axis fixed in the child frame that represents the joint.
+    parent_interframe : ReferenceFrame
+        Intermediate frame of the parent body with respect to which the joint
+        transformation is formulated.
+    child_interframe : ReferenceFrame
+        Intermediate frame of the child body with respect to which the joint
+        transformation is formulated.
+    joint_axis : Vector
+        The axis about which the rotation occurs. Note that the components of
+        this axis are the same in the parent_interframe and child_interframe.
+    kdes : Matrix
+        Kinematical differential equations of the joint.
+
+    Examples
+    =========
+
+    A single pin joint is created from two bodies and has the following basic
+    attributes:
+
+    >>> from sympy.physics.mechanics import RigidBody, PinJoint
+    >>> parent = RigidBody('P')
+    >>> parent
+    P
+    >>> child = RigidBody('C')
+    >>> child
+    C
+    >>> joint = PinJoint('PC', parent, child)
+    >>> joint
+    PinJoint: PC  parent: P  child: C
+    >>> joint.name
+    'PC'
+    >>> joint.parent
+    P
+    >>> joint.child
+    C
+    >>> joint.parent_point
+    P_masscenter
+    >>> joint.child_point
+    C_masscenter
+    >>> joint.parent_axis
+    P_frame.x
+    >>> joint.child_axis
+    C_frame.x
+    >>> joint.coordinates
+    Matrix([[q_PC(t)]])
+    >>> joint.speeds
+    Matrix([[u_PC(t)]])
+    >>> child.frame.ang_vel_in(parent.frame)
+    u_PC(t)*P_frame.x
+    >>> child.frame.dcm(parent.frame)
+    Matrix([
+    [1,             0,            0],
+    [0,  cos(q_PC(t)), sin(q_PC(t))],
+    [0, -sin(q_PC(t)), cos(q_PC(t))]])
+    >>> joint.child_point.pos_from(joint.parent_point)
+    0
+
+    To further demonstrate the use of the pin joint, the kinematics of simple
+    double pendulum that rotates about the Z axis of each connected body can be
+    created as follows.
+
+    >>> from sympy import symbols, trigsimp
+    >>> from sympy.physics.mechanics import RigidBody, PinJoint
+    >>> l1, l2 = symbols('l1 l2')
+
+    First create bodies to represent the fixed ceiling and one to represent
+    each pendulum bob.
+
+    >>> ceiling = RigidBody('C')
+    >>> upper_bob = RigidBody('U')
+    >>> lower_bob = RigidBody('L')
+
+    The first joint will connect the upper bob to the ceiling by a distance of
+    ``l1`` and the joint axis will be about the Z axis for each body.
+
+    >>> ceiling_joint = PinJoint('P1', ceiling, upper_bob,
+    ... child_point=-l1*upper_bob.frame.x,
+    ... joint_axis=ceiling.frame.z)
+
+    The second joint will connect the lower bob to the upper bob by a distance
+    of ``l2`` and the joint axis will also be about the Z axis for each body.
+
+    >>> pendulum_joint = PinJoint('P2', upper_bob, lower_bob,
+    ... child_point=-l2*lower_bob.frame.x,
+    ... joint_axis=upper_bob.frame.z)
+
+    Once the joints are established the kinematics of the connected bodies can
+    be accessed. First the direction cosine matrices of pendulum link relative
+    to the ceiling are found:
+
+    >>> upper_bob.frame.dcm(ceiling.frame)
+    Matrix([
+    [ cos(q_P1(t)), sin(q_P1(t)), 0],
+    [-sin(q_P1(t)), cos(q_P1(t)), 0],
+    [            0,            0, 1]])
+    >>> trigsimp(lower_bob.frame.dcm(ceiling.frame))
+    Matrix([
+    [ cos(q_P1(t) + q_P2(t)), sin(q_P1(t) + q_P2(t)), 0],
+    [-sin(q_P1(t) + q_P2(t)), cos(q_P1(t) + q_P2(t)), 0],
+    [                      0,                      0, 1]])
+
+    The position of the lower bob's masscenter is found with:
+
+    >>> lower_bob.masscenter.pos_from(ceiling.masscenter)
+    l1*U_frame.x + l2*L_frame.x
+
+    The angular velocities of the two pendulum links can be computed with
+    respect to the ceiling.
+
+    >>> upper_bob.frame.ang_vel_in(ceiling.frame)
+    u_P1(t)*C_frame.z
+    >>> lower_bob.frame.ang_vel_in(ceiling.frame)
+    u_P1(t)*C_frame.z + u_P2(t)*U_frame.z
+
+    And finally, the linear velocities of the two pendulum bobs can be computed
+    with respect to the ceiling.
+
+    >>> upper_bob.masscenter.vel(ceiling.frame)
+    l1*u_P1(t)*U_frame.y
+    >>> lower_bob.masscenter.vel(ceiling.frame)
+    l1*u_P1(t)*U_frame.y + l2*(u_P1(t) + u_P2(t))*L_frame.y
+
+    """
+
+    def __init__(self, name, parent, child, coordinates=None, speeds=None,
+                 parent_point=None, child_point=None, parent_interframe=None,
+                 child_interframe=None, parent_axis=None, child_axis=None,
+                 joint_axis=None, parent_joint_pos=None, child_joint_pos=None):
+
+        self._joint_axis = joint_axis
+        super().__init__(name, parent, child, coordinates, speeds, parent_point,
+                         child_point, parent_interframe, child_interframe,
+                         parent_axis, child_axis, parent_joint_pos,
+                         child_joint_pos)
+
+    def __str__(self):
+        return (f'PinJoint: {self.name}  parent: {self.parent}  '
+                f'child: {self.child}')
+
+    @property
+    def joint_axis(self):
+        """Axis about which the child rotates with respect to the parent."""
+        return self._joint_axis
+
+    def _generate_coordinates(self, coordinate):
+        return self._fill_coordinate_list(coordinate, 1, 'q')
+
+    def _generate_speeds(self, speed):
+        return self._fill_coordinate_list(speed, 1, 'u')
+
+    def _orient_frames(self):
+        self._joint_axis = self._axis(self.joint_axis, self.parent_interframe)
+        self.child_interframe.orient_axis(
+            self.parent_interframe, self.joint_axis, self.coordinates[0])
+
+    def _set_angular_velocity(self):
+        self.child_interframe.set_ang_vel(self.parent_interframe, self.speeds[
+            0] * self.joint_axis.normalize())
+
+    def _set_linear_velocity(self):
+        self.child_point.set_pos(self.parent_point, 0)
+        self.parent_point.set_vel(self._parent_frame, 0)
+        self.child_point.set_vel(self._child_frame, 0)
+        self.child.masscenter.v2pt_theory(self.parent_point,
+                                          self._parent_frame, self._child_frame)
+
+
+class PrismaticJoint(Joint):
+    """Prismatic (Sliding) Joint.
+
+    .. image:: PrismaticJoint.svg
+
+    Explanation
+    ===========
+
+    It is defined such that the child body translates with respect to the parent
+    body along the body-fixed joint axis. The location of the joint is defined
+    by two points, one in each body, which coincide when the generalized
+    coordinate is zero. The direction cosine matrix between the
+    parent_interframe and child_interframe is the identity matrix. Therefore,
+    the direction cosine matrix between the parent and child frames is fully
+    defined by the definition of the intermediate frames. The page on the joints
+    framework gives a more detailed explanation of the intermediate frames.
+
+    Parameters
+    ==========
+
+    name : string
+        A unique name for the joint.
+    parent : Particle or RigidBody or Body
+        The parent body of joint.
+    child : Particle or RigidBody or Body
+        The child body of joint.
+    coordinates : dynamicsymbol, optional
+        Generalized coordinates of the joint. The default value is
+        ``dynamicsymbols(f'q_{joint.name}')``.
+    speeds : dynamicsymbol, optional
+        Generalized speeds of joint. The default value is
+        ``dynamicsymbols(f'u_{joint.name}')``.
+    parent_point : Point or Vector, optional
+        Attachment point where the joint is fixed to the parent body. If a
+        vector is provided, then the attachment point is computed by adding the
+        vector to the body's mass center. The default value is the parent's mass
+        center.
+    child_point : Point or Vector, optional
+        Attachment point where the joint is fixed to the child body. If a
+        vector is provided, then the attachment point is computed by adding the
+        vector to the body's mass center. The default value is the child's mass
+        center.
+    parent_axis : Vector, optional
+        .. deprecated:: 1.12
+            Axis fixed in the parent body which aligns with an axis fixed in the
+            child body. The default is the x axis of parent's reference frame.
+            For more information on this deprecation, see
+            :ref:`deprecated-mechanics-joint-axis`.
+    child_axis : Vector, optional
+        .. deprecated:: 1.12
+            Axis fixed in the child body which aligns with an axis fixed in the
+            parent body. The default is the x axis of child's reference frame.
+            For more information on this deprecation, see
+            :ref:`deprecated-mechanics-joint-axis`.
+    parent_interframe : ReferenceFrame, optional
+        Intermediate frame of the parent body with respect to which the joint
+        transformation is formulated. If a Vector is provided then an interframe
+        is created which aligns its X axis with the given vector. The default
+        value is the parent's own frame.
+    child_interframe : ReferenceFrame, optional
+        Intermediate frame of the child body with respect to which the joint
+        transformation is formulated. If a Vector is provided then an interframe
+        is created which aligns its X axis with the given vector. The default
+        value is the child's own frame.
+    joint_axis : Vector
+        The axis along which the translation occurs. Note that the components
+        of this axis are the same in the parent_interframe and child_interframe.
+    parent_joint_pos : Point or Vector, optional
+        .. deprecated:: 1.12
+            This argument is replaced by parent_point and will be removed in a
+            future version.
+            See :ref:`deprecated-mechanics-joint-pos` for more information.
+    child_joint_pos : Point or Vector, optional
+        .. deprecated:: 1.12
+            This argument is replaced by child_point and will be removed in a
+            future version.
+            See :ref:`deprecated-mechanics-joint-pos` for more information.
+
+    Attributes
+    ==========
+
+    name : string
+        The joint's name.
+    parent : Particle or RigidBody or Body
+        The joint's parent body.
+    child : Particle or RigidBody or Body
+        The joint's child body.
+    coordinates : Matrix
+        Matrix of the joint's generalized coordinates.
+    speeds : Matrix
+        Matrix of the joint's generalized speeds.
+    parent_point : Point
+        Attachment point where the joint is fixed to the parent body.
+    child_point : Point
+        Attachment point where the joint is fixed to the child body.
+    parent_axis : Vector
+        The axis fixed in the parent frame that represents the joint.
+    child_axis : Vector
+        The axis fixed in the child frame that represents the joint.
+    parent_interframe : ReferenceFrame
+        Intermediate frame of the parent body with respect to which the joint
+        transformation is formulated.
+    child_interframe : ReferenceFrame
+        Intermediate frame of the child body with respect to which the joint
+        transformation is formulated.
+    kdes : Matrix
+        Kinematical differential equations of the joint.
+
+    Examples
+    =========
+
+    A single prismatic joint is created from two bodies and has the following
+    basic attributes:
+
+    >>> from sympy.physics.mechanics import RigidBody, PrismaticJoint
+    >>> parent = RigidBody('P')
+    >>> parent
+    P
+    >>> child = RigidBody('C')
+    >>> child
+    C
+    >>> joint = PrismaticJoint('PC', parent, child)
+    >>> joint
+    PrismaticJoint: PC  parent: P  child: C
+    >>> joint.name
+    'PC'
+    >>> joint.parent
+    P
+    >>> joint.child
+    C
+    >>> joint.parent_point
+    P_masscenter
+    >>> joint.child_point
+    C_masscenter
+    >>> joint.parent_axis
+    P_frame.x
+    >>> joint.child_axis
+    C_frame.x
+    >>> joint.coordinates
+    Matrix([[q_PC(t)]])
+    >>> joint.speeds
+    Matrix([[u_PC(t)]])
+    >>> child.frame.ang_vel_in(parent.frame)
+    0
+    >>> child.frame.dcm(parent.frame)
+    Matrix([
+    [1, 0, 0],
+    [0, 1, 0],
+    [0, 0, 1]])
+    >>> joint.child_point.pos_from(joint.parent_point)
+    q_PC(t)*P_frame.x
+
+    To further demonstrate the use of the prismatic joint, the kinematics of two
+    masses sliding, one moving relative to a fixed body and the other relative
+    to the moving body. about the X axis of each connected body can be created
+    as follows.
+
+    >>> from sympy.physics.mechanics import PrismaticJoint, RigidBody
+
+    First create bodies to represent the fixed ceiling and one to represent
+    a particle.
+
+    >>> wall = RigidBody('W')
+    >>> Part1 = RigidBody('P1')
+    >>> Part2 = RigidBody('P2')
+
+    The first joint will connect the particle to the ceiling and the
+    joint axis will be about the X axis for each body.
+
+    >>> J1 = PrismaticJoint('J1', wall, Part1)
+
+    The second joint will connect the second particle to the first particle
+    and the joint axis will also be about the X axis for each body.
+
+    >>> J2 = PrismaticJoint('J2', Part1, Part2)
+
+    Once the joint is established the kinematics of the connected bodies can
+    be accessed. First the direction cosine matrices of Part relative
+    to the ceiling are found:
+
+    >>> Part1.frame.dcm(wall.frame)
+    Matrix([
+    [1, 0, 0],
+    [0, 1, 0],
+    [0, 0, 1]])
+
+    >>> Part2.frame.dcm(wall.frame)
+    Matrix([
+    [1, 0, 0],
+    [0, 1, 0],
+    [0, 0, 1]])
+
+    The position of the particles' masscenter is found with:
+
+    >>> Part1.masscenter.pos_from(wall.masscenter)
+    q_J1(t)*W_frame.x
+
+    >>> Part2.masscenter.pos_from(wall.masscenter)
+    q_J1(t)*W_frame.x + q_J2(t)*P1_frame.x
+
+    The angular velocities of the two particle links can be computed with
+    respect to the ceiling.
+
+    >>> Part1.frame.ang_vel_in(wall.frame)
+    0
+
+    >>> Part2.frame.ang_vel_in(wall.frame)
+    0
+
+    And finally, the linear velocities of the two particles can be computed
+    with respect to the ceiling.
+
+    >>> Part1.masscenter.vel(wall.frame)
+    u_J1(t)*W_frame.x
+
+    >>> Part2.masscenter.vel(wall.frame)
+    u_J1(t)*W_frame.x + Derivative(q_J2(t), t)*P1_frame.x
+
+    """
+
+    def __init__(self, name, parent, child, coordinates=None, speeds=None,
+                 parent_point=None, child_point=None, parent_interframe=None,
+                 child_interframe=None, parent_axis=None, child_axis=None,
+                 joint_axis=None, parent_joint_pos=None, child_joint_pos=None):
+
+        self._joint_axis = joint_axis
+        super().__init__(name, parent, child, coordinates, speeds, parent_point,
+                         child_point, parent_interframe, child_interframe,
+                         parent_axis, child_axis, parent_joint_pos,
+                         child_joint_pos)
+
+    def __str__(self):
+        return (f'PrismaticJoint: {self.name}  parent: {self.parent}  '
+                f'child: {self.child}')
+
+    @property
+    def joint_axis(self):
+        """Axis along which the child translates with respect to the parent."""
+        return self._joint_axis
+
+    def _generate_coordinates(self, coordinate):
+        return self._fill_coordinate_list(coordinate, 1, 'q')
+
+    def _generate_speeds(self, speed):
+        return self._fill_coordinate_list(speed, 1, 'u')
+
+    def _orient_frames(self):
+        self._joint_axis = self._axis(self.joint_axis, self.parent_interframe)
+        self.child_interframe.orient_axis(
+            self.parent_interframe, self.joint_axis, 0)
+
+    def _set_angular_velocity(self):
+        self.child_interframe.set_ang_vel(self.parent_interframe, 0)
+
+    def _set_linear_velocity(self):
+        axis = self.joint_axis.normalize()
+        self.child_point.set_pos(self.parent_point, self.coordinates[0] * axis)
+        self.parent_point.set_vel(self._parent_frame, 0)
+        self.child_point.set_vel(self._child_frame, 0)
+        self.child_point.set_vel(self._parent_frame, self.speeds[0] * axis)
+        self.child.masscenter.set_vel(self._parent_frame, self.speeds[0] * axis)
+
+
+class CylindricalJoint(Joint):
+    """Cylindrical Joint.
+
+    .. image:: CylindricalJoint.svg
+        :align: center
+        :width: 600
+
+    Explanation
+    ===========
+
+    A cylindrical joint is defined such that the child body both rotates about
+    and translates along the body-fixed joint axis with respect to the parent
+    body. The joint axis is both the rotation axis and translation axis. The
+    location of the joint is defined by two points, one in each body, which
+    coincide when the generalized coordinate corresponding to the translation is
+    zero. The direction cosine matrix between the child interframe and parent
+    interframe is formed using a simple rotation about the joint axis. The page
+    on the joints framework gives a more detailed explanation of the
+    intermediate frames.
+
+    Parameters
+    ==========
+
+    name : string
+        A unique name for the joint.
+    parent : Particle or RigidBody or Body
+        The parent body of joint.
+    child : Particle or RigidBody or Body
+        The child body of joint.
+    rotation_coordinate : dynamicsymbol, optional
+        Generalized coordinate corresponding to the rotation angle. The default
+        value is ``dynamicsymbols(f'q0_{joint.name}')``.
+    translation_coordinate : dynamicsymbol, optional
+        Generalized coordinate corresponding to the translation distance. The
+        default value is ``dynamicsymbols(f'q1_{joint.name}')``.
+    rotation_speed : dynamicsymbol, optional
+        Generalized speed corresponding to the angular velocity. The default
+        value is ``dynamicsymbols(f'u0_{joint.name}')``.
+    translation_speed : dynamicsymbol, optional
+        Generalized speed corresponding to the translation velocity. The default
+        value is ``dynamicsymbols(f'u1_{joint.name}')``.
+    parent_point : Point or Vector, optional
+        Attachment point where the joint is fixed to the parent body. If a
+        vector is provided, then the attachment point is computed by adding the
+        vector to the body's mass center. The default value is the parent's mass
+        center.
+    child_point : Point or Vector, optional
+        Attachment point where the joint is fixed to the child body. If a
+        vector is provided, then the attachment point is computed by adding the
+        vector to the body's mass center. The default value is the child's mass
+        center.
+    parent_interframe : ReferenceFrame, optional
+        Intermediate frame of the parent body with respect to which the joint
+        transformation is formulated. If a Vector is provided then an interframe
+        is created which aligns its X axis with the given vector. The default
+        value is the parent's own frame.
+    child_interframe : ReferenceFrame, optional
+        Intermediate frame of the child body with respect to which the joint
+        transformation is formulated. If a Vector is provided then an interframe
+        is created which aligns its X axis with the given vector. The default
+        value is the child's own frame.
+    joint_axis : Vector, optional
+        The rotation as well as translation axis. Note that the components of
+        this axis are the same in the parent_interframe and child_interframe.
+
+    Attributes
+    ==========
+
+    name : string
+        The joint's name.
+    parent : Particle or RigidBody or Body
+        The joint's parent body.
+    child : Particle or RigidBody or Body
+        The joint's child body.
+    rotation_coordinate : dynamicsymbol
+        Generalized coordinate corresponding to the rotation angle.
+    translation_coordinate : dynamicsymbol
+        Generalized coordinate corresponding to the translation distance.
+    rotation_speed : dynamicsymbol
+        Generalized speed corresponding to the angular velocity.
+    translation_speed : dynamicsymbol
+        Generalized speed corresponding to the translation velocity.
+    coordinates : Matrix
+        Matrix of the joint's generalized coordinates.
+    speeds : Matrix
+        Matrix of the joint's generalized speeds.
+    parent_point : Point
+        Attachment point where the joint is fixed to the parent body.
+    child_point : Point
+        Attachment point where the joint is fixed to the child body.
+    parent_interframe : ReferenceFrame
+        Intermediate frame of the parent body with respect to which the joint
+        transformation is formulated.
+    child_interframe : ReferenceFrame
+        Intermediate frame of the child body with respect to which the joint
+        transformation is formulated.
+    kdes : Matrix
+        Kinematical differential equations of the joint.
+    joint_axis : Vector
+        The axis of rotation and translation.
+
+    Examples
+    =========
+
+    A single cylindrical joint is created between two bodies and has the
+    following basic attributes:
+
+    >>> from sympy.physics.mechanics import RigidBody, CylindricalJoint
+    >>> parent = RigidBody('P')
+    >>> parent
+    P
+    >>> child = RigidBody('C')
+    >>> child
+    C
+    >>> joint = CylindricalJoint('PC', parent, child)
+    >>> joint
+    CylindricalJoint: PC  parent: P  child: C
+    >>> joint.name
+    'PC'
+    >>> joint.parent
+    P
+    >>> joint.child
+    C
+    >>> joint.parent_point
+    P_masscenter
+    >>> joint.child_point
+    C_masscenter
+    >>> joint.parent_axis
+    P_frame.x
+    >>> joint.child_axis
+    C_frame.x
+    >>> joint.coordinates
+    Matrix([
+    [q0_PC(t)],
+    [q1_PC(t)]])
+    >>> joint.speeds
+    Matrix([
+    [u0_PC(t)],
+    [u1_PC(t)]])
+    >>> child.frame.ang_vel_in(parent.frame)
+    u0_PC(t)*P_frame.x
+    >>> child.frame.dcm(parent.frame)
+    Matrix([
+    [1,              0,             0],
+    [0,  cos(q0_PC(t)), sin(q0_PC(t))],
+    [0, -sin(q0_PC(t)), cos(q0_PC(t))]])
+    >>> joint.child_point.pos_from(joint.parent_point)
+    q1_PC(t)*P_frame.x
+    >>> child.masscenter.vel(parent.frame)
+    u1_PC(t)*P_frame.x
+
+    To further demonstrate the use of the cylindrical joint, the kinematics of
+    two cylindrical joints perpendicular to each other can be created as follows.
+
+    >>> from sympy import symbols
+    >>> from sympy.physics.mechanics import RigidBody, CylindricalJoint
+    >>> r, l, w = symbols('r l w')
+
+    First create bodies to represent the fixed floor with a fixed pole on it.
+    The second body represents a freely moving tube around that pole. The third
+    body represents a solid flag freely translating along and rotating around
+    the Y axis of the tube.
+
+    >>> floor = RigidBody('floor')
+    >>> tube = RigidBody('tube')
+    >>> flag = RigidBody('flag')
+
+    The first joint will connect the first tube to the floor with it translating
+    along and rotating around the Z axis of both bodies.
+
+    >>> floor_joint = CylindricalJoint('C1', floor, tube, joint_axis=floor.z)
+
+    The second joint will connect the tube perpendicular to the flag along the Y
+    axis of both the tube and the flag, with the joint located at a distance
+    ``r`` from the tube's center of mass and a combination of the distances
+    ``l`` and ``w`` from the flag's center of mass.
+
+    >>> flag_joint = CylindricalJoint('C2', tube, flag,
+    ...                               parent_point=r * tube.y,
+    ...                               child_point=-w * flag.y + l * flag.z,
+    ...                               joint_axis=tube.y)
+
+    Once the joints are established the kinematics of the connected bodies can
+    be accessed. First the direction cosine matrices of both the body and the
+    flag relative to the floor are found:
+
+    >>> tube.frame.dcm(floor.frame)
+    Matrix([
+    [ cos(q0_C1(t)), sin(q0_C1(t)), 0],
+    [-sin(q0_C1(t)), cos(q0_C1(t)), 0],
+    [             0,             0, 1]])
+    >>> flag.frame.dcm(floor.frame)
+    Matrix([
+    [cos(q0_C1(t))*cos(q0_C2(t)), sin(q0_C1(t))*cos(q0_C2(t)), -sin(q0_C2(t))],
+    [             -sin(q0_C1(t)),               cos(q0_C1(t)),              0],
+    [sin(q0_C2(t))*cos(q0_C1(t)), sin(q0_C1(t))*sin(q0_C2(t)),  cos(q0_C2(t))]])
+
+    The position of the flag's center of mass is found with:
+
+    >>> flag.masscenter.pos_from(floor.masscenter)
+    q1_C1(t)*floor_frame.z + (r + q1_C2(t))*tube_frame.y + w*flag_frame.y - l*flag_frame.z
+
+    The angular velocities of the two tubes can be computed with respect to the
+    floor.
+
+    >>> tube.frame.ang_vel_in(floor.frame)
+    u0_C1(t)*floor_frame.z
+    >>> flag.frame.ang_vel_in(floor.frame)
+    u0_C1(t)*floor_frame.z + u0_C2(t)*tube_frame.y
+
+    Finally, the linear velocities of the two tube centers of mass can be
+    computed with respect to the floor, while expressed in the tube's frame.
+
+    >>> tube.masscenter.vel(floor.frame).to_matrix(tube.frame)
+    Matrix([
+    [       0],
+    [       0],
+    [u1_C1(t)]])
+    >>> flag.masscenter.vel(floor.frame).to_matrix(tube.frame).simplify()
+    Matrix([
+    [-l*u0_C2(t)*cos(q0_C2(t)) - r*u0_C1(t) - w*u0_C1(t) - q1_C2(t)*u0_C1(t)],
+    [                    -l*u0_C1(t)*sin(q0_C2(t)) + Derivative(q1_C2(t), t)],
+    [                                    l*u0_C2(t)*sin(q0_C2(t)) + u1_C1(t)]])
+
+    """
+
+    def __init__(self, name, parent, child, rotation_coordinate=None,
+                 translation_coordinate=None, rotation_speed=None,
+                 translation_speed=None, parent_point=None, child_point=None,
+                 parent_interframe=None, child_interframe=None,
+                 joint_axis=None):
+        self._joint_axis = joint_axis
+        coordinates = (rotation_coordinate, translation_coordinate)
+        speeds = (rotation_speed, translation_speed)
+        super().__init__(name, parent, child, coordinates, speeds,
+                         parent_point, child_point,
+                         parent_interframe=parent_interframe,
+                         child_interframe=child_interframe)
+
+    def __str__(self):
+        return (f'CylindricalJoint: {self.name}  parent: {self.parent}  '
+                f'child: {self.child}')
+
+    @property
+    def joint_axis(self):
+        """Axis about and along which the rotation and translation occurs."""
+        return self._joint_axis
+
+    @property
+    def rotation_coordinate(self):
+        """Generalized coordinate corresponding to the rotation angle."""
+        return self.coordinates[0]
+
+    @property
+    def translation_coordinate(self):
+        """Generalized coordinate corresponding to the translation distance."""
+        return self.coordinates[1]
+
+    @property
+    def rotation_speed(self):
+        """Generalized speed corresponding to the angular velocity."""
+        return self.speeds[0]
+
+    @property
+    def translation_speed(self):
+        """Generalized speed corresponding to the translation velocity."""
+        return self.speeds[1]
+
+    def _generate_coordinates(self, coordinates):
+        return self._fill_coordinate_list(coordinates, 2, 'q')
+
+    def _generate_speeds(self, speeds):
+        return self._fill_coordinate_list(speeds, 2, 'u')
+
+    def _orient_frames(self):
+        self._joint_axis = self._axis(self.joint_axis, self.parent_interframe)
+        self.child_interframe.orient_axis(
+            self.parent_interframe, self.joint_axis, self.rotation_coordinate)
+
+    def _set_angular_velocity(self):
+        self.child_interframe.set_ang_vel(
+            self.parent_interframe,
+            self.rotation_speed * self.joint_axis.normalize())
+
+    def _set_linear_velocity(self):
+        self.child_point.set_pos(
+            self.parent_point,
+            self.translation_coordinate * self.joint_axis.normalize())
+        self.parent_point.set_vel(self._parent_frame, 0)
+        self.child_point.set_vel(self._child_frame, 0)
+        self.child_point.set_vel(
+            self._parent_frame,
+            self.translation_speed * self.joint_axis.normalize())
+        self.child.masscenter.v2pt_theory(self.child_point, self._parent_frame,
+                                          self.child_interframe)
+
+
+class PlanarJoint(Joint):
+    """Planar Joint.
+
+    .. raw:: html
+        :file: ../../../doc/src/modules/physics/mechanics/api/PlanarJoint.svg
+
+    Explanation
+    ===========
+
+    A planar joint is defined such that the child body translates over a fixed
+    plane of the parent body as well as rotate about the rotation axis, which
+    is perpendicular to that plane. The origin of this plane is the
+    ``parent_point`` and the plane is spanned by two nonparallel planar vectors.
+    The location of the ``child_point`` is based on the planar vectors
+    ($\\vec{v}_1$, $\\vec{v}_2$) and generalized coordinates ($q_1$, $q_2$),
+    i.e. $\\vec{r} = q_1 \\hat{v}_1 + q_2 \\hat{v}_2$. The direction cosine
+    matrix between the ``child_interframe`` and ``parent_interframe`` is formed
+    using a simple rotation ($q_0$) about the rotation axis.
+
+    In order to simplify the definition of the ``PlanarJoint``, the
+    ``rotation_axis`` and ``planar_vectors`` are set to be the unit vectors of
+    the ``parent_interframe`` according to the table below. This ensures that
+    you can only define these vectors by creating a separate frame and supplying
+    that as the interframe. If you however would only like to supply the normals
+    of the plane with respect to the parent and child bodies, then you can also
+    supply those to the ``parent_interframe`` and ``child_interframe``
+    arguments. An example of both of these cases is in the examples section
+    below and the page on the joints framework provides a more detailed
+    explanation of the intermediate frames.
+
+    .. list-table::
+
+        * - ``rotation_axis``
+          - ``parent_interframe.x``
+        * - ``planar_vectors[0]``
+          - ``parent_interframe.y``
+        * - ``planar_vectors[1]``
+          - ``parent_interframe.z``
+
+    Parameters
+    ==========
+
+    name : string
+        A unique name for the joint.
+    parent : Particle or RigidBody or Body
+        The parent body of joint.
+    child : Particle or RigidBody or Body
+        The child body of joint.
+    rotation_coordinate : dynamicsymbol, optional
+        Generalized coordinate corresponding to the rotation angle. The default
+        value is ``dynamicsymbols(f'q0_{joint.name}')``.
+    planar_coordinates : iterable of dynamicsymbols, optional
+        Two generalized coordinates used for the planar translation. The default
+        value is ``dynamicsymbols(f'q1_{joint.name} q2_{joint.name}')``.
+    rotation_speed : dynamicsymbol, optional
+        Generalized speed corresponding to the angular velocity. The default
+        value is ``dynamicsymbols(f'u0_{joint.name}')``.
+    planar_speeds : dynamicsymbols, optional
+        Two generalized speeds used for the planar translation velocity. The
+        default value is ``dynamicsymbols(f'u1_{joint.name} u2_{joint.name}')``.
+    parent_point : Point or Vector, optional
+        Attachment point where the joint is fixed to the parent body. If a
+        vector is provided, then the attachment point is computed by adding the
+        vector to the body's mass center. The default value is the parent's mass
+        center.
+    child_point : Point or Vector, optional
+        Attachment point where the joint is fixed to the child body. If a
+        vector is provided, then the attachment point is computed by adding the
+        vector to the body's mass center. The default value is the child's mass
+        center.
+    parent_interframe : ReferenceFrame, optional
+        Intermediate frame of the parent body with respect to which the joint
+        transformation is formulated. If a Vector is provided then an interframe
+        is created which aligns its X axis with the given vector. The default
+        value is the parent's own frame.
+    child_interframe : ReferenceFrame, optional
+        Intermediate frame of the child body with respect to which the joint
+        transformation is formulated. If a Vector is provided then an interframe
+        is created which aligns its X axis with the given vector. The default
+        value is the child's own frame.
+
+    Attributes
+    ==========
+
+    name : string
+        The joint's name.
+    parent : Particle or RigidBody or Body
+        The joint's parent body.
+    child : Particle or RigidBody or Body
+        The joint's child body.
+    rotation_coordinate : dynamicsymbol
+        Generalized coordinate corresponding to the rotation angle.
+    planar_coordinates : Matrix
+        Two generalized coordinates used for the planar translation.
+    rotation_speed : dynamicsymbol
+        Generalized speed corresponding to the angular velocity.
+    planar_speeds : Matrix
+        Two generalized speeds used for the planar translation velocity.
+    coordinates : Matrix
+        Matrix of the joint's generalized coordinates.
+    speeds : Matrix
+        Matrix of the joint's generalized speeds.
+    parent_point : Point
+        Attachment point where the joint is fixed to the parent body.
+    child_point : Point
+        Attachment point where the joint is fixed to the child body.
+    parent_interframe : ReferenceFrame
+        Intermediate frame of the parent body with respect to which the joint
+        transformation is formulated.
+    child_interframe : ReferenceFrame
+        Intermediate frame of the child body with respect to which the joint
+        transformation is formulated.
+    kdes : Matrix
+        Kinematical differential equations of the joint.
+    rotation_axis : Vector
+        The axis about which the rotation occurs.
+    planar_vectors : list
+        The vectors that describe the planar translation directions.
+
+    Examples
+    =========
+
+    A single planar joint is created between two bodies and has the following
+    basic attributes:
+
+    >>> from sympy.physics.mechanics import RigidBody, PlanarJoint
+    >>> parent = RigidBody('P')
+    >>> parent
+    P
+    >>> child = RigidBody('C')
+    >>> child
+    C
+    >>> joint = PlanarJoint('PC', parent, child)
+    >>> joint
+    PlanarJoint: PC  parent: P  child: C
+    >>> joint.name
+    'PC'
+    >>> joint.parent
+    P
+    >>> joint.child
+    C
+    >>> joint.parent_point
+    P_masscenter
+    >>> joint.child_point
+    C_masscenter
+    >>> joint.rotation_axis
+    P_frame.x
+    >>> joint.planar_vectors
+    [P_frame.y, P_frame.z]
+    >>> joint.rotation_coordinate
+    q0_PC(t)
+    >>> joint.planar_coordinates
+    Matrix([
+    [q1_PC(t)],
+    [q2_PC(t)]])
+    >>> joint.coordinates
+    Matrix([
+    [q0_PC(t)],
+    [q1_PC(t)],
+    [q2_PC(t)]])
+    >>> joint.rotation_speed
+    u0_PC(t)
+    >>> joint.planar_speeds
+    Matrix([
+    [u1_PC(t)],
+    [u2_PC(t)]])
+    >>> joint.speeds
+    Matrix([
+    [u0_PC(t)],
+    [u1_PC(t)],
+    [u2_PC(t)]])
+    >>> child.frame.ang_vel_in(parent.frame)
+    u0_PC(t)*P_frame.x
+    >>> child.frame.dcm(parent.frame)
+    Matrix([
+    [1,              0,             0],
+    [0,  cos(q0_PC(t)), sin(q0_PC(t))],
+    [0, -sin(q0_PC(t)), cos(q0_PC(t))]])
+    >>> joint.child_point.pos_from(joint.parent_point)
+    q1_PC(t)*P_frame.y + q2_PC(t)*P_frame.z
+    >>> child.masscenter.vel(parent.frame)
+    u1_PC(t)*P_frame.y + u2_PC(t)*P_frame.z
+
+    To further demonstrate the use of the planar joint, the kinematics of a
+    block sliding on a slope, can be created as follows.
+
+    >>> from sympy import symbols
+    >>> from sympy.physics.mechanics import PlanarJoint, RigidBody, ReferenceFrame
+    >>> a, d, h = symbols('a d h')
+
+    First create bodies to represent the slope and the block.
+
+    >>> ground = RigidBody('G')
+    >>> block = RigidBody('B')
+
+    To define the slope you can either define the plane by specifying the
+    ``planar_vectors`` or/and the ``rotation_axis``. However it is advisable to
+    create a rotated intermediate frame, so that the ``parent_vectors`` and
+    ``rotation_axis`` will be the unit vectors of this intermediate frame.
+
+    >>> slope = ReferenceFrame('A')
+    >>> slope.orient_axis(ground.frame, ground.y, a)
+
+    The planar joint can be created using these bodies and intermediate frame.
+    We can specify the origin of the slope to be ``d`` above the slope's center
+    of mass and the block's center of mass to be a distance ``h`` above the
+    slope's surface. Note that we can specify the normal of the plane using the
+    rotation axis argument.
+
+    >>> joint = PlanarJoint('PC', ground, block, parent_point=d * ground.x,
+    ...                     child_point=-h * block.x, parent_interframe=slope)
+
+    Once the joint is established the kinematics of the bodies can be accessed.
+    First the ``rotation_axis``, which is normal to the plane and the
+    ``plane_vectors``, can be found.
+
+    >>> joint.rotation_axis
+    A.x
+    >>> joint.planar_vectors
+    [A.y, A.z]
+
+    The direction cosine matrix of the block with respect to the ground can be
+    found with:
+
+    >>> block.frame.dcm(ground.frame)
+    Matrix([
+    [              cos(a),              0,              -sin(a)],
+    [sin(a)*sin(q0_PC(t)),  cos(q0_PC(t)), sin(q0_PC(t))*cos(a)],
+    [sin(a)*cos(q0_PC(t)), -sin(q0_PC(t)), cos(a)*cos(q0_PC(t))]])
+
+    The angular velocity of the block can be computed with respect to the
+    ground.
+
+    >>> block.frame.ang_vel_in(ground.frame)
+    u0_PC(t)*A.x
+
+    The position of the block's center of mass can be found with:
+
+    >>> block.masscenter.pos_from(ground.masscenter)
+    d*G_frame.x + h*B_frame.x + q1_PC(t)*A.y + q2_PC(t)*A.z
+
+    Finally, the linear velocity of the block's center of mass can be
+    computed with respect to the ground.
+
+    >>> block.masscenter.vel(ground.frame)
+    u1_PC(t)*A.y + u2_PC(t)*A.z
+
+    In some cases it could be your preference to only define the normals of the
+    plane with respect to both bodies. This can most easily be done by supplying
+    vectors to the ``interframe`` arguments. What will happen in this case is
+    that an interframe will be created with its ``x`` axis aligned with the
+    provided vector. For a further explanation of how this is done see the notes
+    of the ``Joint`` class. In the code below, the above example (with the block
+    on the slope) is recreated by supplying vectors to the interframe arguments.
+    Note that the previously described option is however more computationally
+    efficient, because the algorithm now has to compute the rotation angle
+    between the provided vector and the 'x' axis.
+
+    >>> from sympy import symbols, cos, sin
+    >>> from sympy.physics.mechanics import PlanarJoint, RigidBody
+    >>> a, d, h = symbols('a d h')
+    >>> ground = RigidBody('G')
+    >>> block = RigidBody('B')
+    >>> joint = PlanarJoint(
+    ...     'PC', ground, block, parent_point=d * ground.x,
+    ...     child_point=-h * block.x, child_interframe=block.x,
+    ...     parent_interframe=cos(a) * ground.x + sin(a) * ground.z)
+    >>> block.frame.dcm(ground.frame).simplify()
+    Matrix([
+    [               cos(a),              0,               sin(a)],
+    [-sin(a)*sin(q0_PC(t)),  cos(q0_PC(t)), sin(q0_PC(t))*cos(a)],
+    [-sin(a)*cos(q0_PC(t)), -sin(q0_PC(t)), cos(a)*cos(q0_PC(t))]])
+
+    """
+
+    def __init__(self, name, parent, child, rotation_coordinate=None,
+                 planar_coordinates=None, rotation_speed=None,
+                 planar_speeds=None, parent_point=None, child_point=None,
+                 parent_interframe=None, child_interframe=None):
+        # A ready to merge implementation of setting the planar_vectors and
+        # rotation_axis was added and removed in PR #24046
+        coordinates = (rotation_coordinate, planar_coordinates)
+        speeds = (rotation_speed, planar_speeds)
+        super().__init__(name, parent, child, coordinates, speeds,
+                         parent_point, child_point,
+                         parent_interframe=parent_interframe,
+                         child_interframe=child_interframe)
+
+    def __str__(self):
+        return (f'PlanarJoint: {self.name}  parent: {self.parent}  '
+                f'child: {self.child}')
+
+    @property
+    def rotation_coordinate(self):
+        """Generalized coordinate corresponding to the rotation angle."""
+        return self.coordinates[0]
+
+    @property
+    def planar_coordinates(self):
+        """Two generalized coordinates used for the planar translation."""
+        return self.coordinates[1:, 0]
+
+    @property
+    def rotation_speed(self):
+        """Generalized speed corresponding to the angular velocity."""
+        return self.speeds[0]
+
+    @property
+    def planar_speeds(self):
+        """Two generalized speeds used for the planar translation velocity."""
+        return self.speeds[1:, 0]
+
+    @property
+    def rotation_axis(self):
+        """The axis about which the rotation occurs."""
+        return self.parent_interframe.x
+
+    @property
+    def planar_vectors(self):
+        """The vectors that describe the planar translation directions."""
+        return [self.parent_interframe.y, self.parent_interframe.z]
+
+    def _generate_coordinates(self, coordinates):
+        rotation_speed = self._fill_coordinate_list(coordinates[0], 1, 'q',
+                                                    number_single=True)
+        planar_speeds = self._fill_coordinate_list(coordinates[1], 2, 'q', 1)
+        return rotation_speed.col_join(planar_speeds)
+
+    def _generate_speeds(self, speeds):
+        rotation_speed = self._fill_coordinate_list(speeds[0], 1, 'u',
+                                                    number_single=True)
+        planar_speeds = self._fill_coordinate_list(speeds[1], 2, 'u', 1)
+        return rotation_speed.col_join(planar_speeds)
+
+    def _orient_frames(self):
+        self.child_interframe.orient_axis(
+            self.parent_interframe, self.rotation_axis,
+            self.rotation_coordinate)
+
+    def _set_angular_velocity(self):
+        self.child_interframe.set_ang_vel(
+            self.parent_interframe,
+            self.rotation_speed * self.rotation_axis)
+
+    def _set_linear_velocity(self):
+        self.child_point.set_pos(
+            self.parent_point,
+            self.planar_coordinates[0] * self.planar_vectors[0] +
+            self.planar_coordinates[1] * self.planar_vectors[1])
+        self.parent_point.set_vel(self.parent_interframe, 0)
+        self.child_point.set_vel(self.child_interframe, 0)
+        self.child_point.set_vel(
+            self._parent_frame, self.planar_speeds[0] * self.planar_vectors[0] +
+            self.planar_speeds[1] * self.planar_vectors[1])
+        self.child.masscenter.v2pt_theory(self.child_point, self._parent_frame,
+                                          self._child_frame)
+
+
+class SphericalJoint(Joint):
+    """Spherical (Ball-and-Socket) Joint.
+
+    .. image:: SphericalJoint.svg
+        :align: center
+        :width: 600
+
+    Explanation
+    ===========
+
+    A spherical joint is defined such that the child body is free to rotate in
+    any direction, without allowing a translation of the ``child_point``. As can
+    also be seen in the image, the ``parent_point`` and ``child_point`` are
+    fixed on top of each other, i.e. the ``joint_point``. This rotation is
+    defined using the :func:`parent_interframe.orient(child_interframe,
+    rot_type, amounts, rot_order)
+    <sympy.physics.vector.frame.ReferenceFrame.orient>` method. The default
+    rotation consists of three relative rotations, i.e. body-fixed rotations.
+    Based on the direction cosine matrix following from these rotations, the
+    angular velocity is computed based on the generalized coordinates and
+    generalized speeds.
+
+    Parameters
+    ==========
+
+    name : string
+        A unique name for the joint.
+    parent : Particle or RigidBody or Body
+        The parent body of joint.
+    child : Particle or RigidBody or Body
+        The child body of joint.
+    coordinates: iterable of dynamicsymbols, optional
+        Generalized coordinates of the joint.
+    speeds : iterable of dynamicsymbols, optional
+        Generalized speeds of joint.
+    parent_point : Point or Vector, optional
+        Attachment point where the joint is fixed to the parent body. If a
+        vector is provided, then the attachment point is computed by adding the
+        vector to the body's mass center. The default value is the parent's mass
+        center.
+    child_point : Point or Vector, optional
+        Attachment point where the joint is fixed to the child body. If a
+        vector is provided, then the attachment point is computed by adding the
+        vector to the body's mass center. The default value is the child's mass
+        center.
+    parent_interframe : ReferenceFrame, optional
+        Intermediate frame of the parent body with respect to which the joint
+        transformation is formulated. If a Vector is provided then an interframe
+        is created which aligns its X axis with the given vector. The default
+        value is the parent's own frame.
+    child_interframe : ReferenceFrame, optional
+        Intermediate frame of the child body with respect to which the joint
+        transformation is formulated. If a Vector is provided then an interframe
+        is created which aligns its X axis with the given vector. The default
+        value is the child's own frame.
+    rot_type : str, optional
+        The method used to generate the direction cosine matrix. Supported
+        methods are:
+
+        - ``'Body'``: three successive rotations about new intermediate axes,
+          also called "Euler and Tait-Bryan angles"
+        - ``'Space'``: three successive rotations about the parent frames' unit
+          vectors
+
+        The default method is ``'Body'``.
+    amounts :
+        Expressions defining the rotation angles or direction cosine matrix.
+        These must match the ``rot_type``. See examples below for details. The
+        input types are:
+
+        - ``'Body'``: 3-tuple of expressions, symbols, or functions
+        - ``'Space'``: 3-tuple of expressions, symbols, or functions
+
+        The default amounts are the given ``coordinates``.
+    rot_order : str or int, optional
+        If applicable, the order of the successive of rotations. The string
+        ``'123'`` and integer ``123`` are equivalent, for example. Required for
+        ``'Body'`` and ``'Space'``. The default value is ``123``.
+
+    Attributes
+    ==========
+
+    name : string
+        The joint's name.
+    parent : Particle or RigidBody or Body
+        The joint's parent body.
+    child : Particle or RigidBody or Body
+        The joint's child body.
+    coordinates : Matrix
+        Matrix of the joint's generalized coordinates.
+    speeds : Matrix
+        Matrix of the joint's generalized speeds.
+    parent_point : Point
+        Attachment point where the joint is fixed to the parent body.
+    child_point : Point
+        Attachment point where the joint is fixed to the child body.
+    parent_interframe : ReferenceFrame
+        Intermediate frame of the parent body with respect to which the joint
+        transformation is formulated.
+    child_interframe : ReferenceFrame
+        Intermediate frame of the child body with respect to which the joint
+        transformation is formulated.
+    kdes : Matrix
+        Kinematical differential equations of the joint.
+
+    Examples
+    =========
+
+    A single spherical joint is created from two bodies and has the following
+    basic attributes:
+
+    >>> from sympy.physics.mechanics import RigidBody, SphericalJoint
+    >>> parent = RigidBody('P')
+    >>> parent
+    P
+    >>> child = RigidBody('C')
+    >>> child
+    C
+    >>> joint = SphericalJoint('PC', parent, child)
+    >>> joint
+    SphericalJoint: PC  parent: P  child: C
+    >>> joint.name
+    'PC'
+    >>> joint.parent
+    P
+    >>> joint.child
+    C
+    >>> joint.parent_point
+    P_masscenter
+    >>> joint.child_point
+    C_masscenter
+    >>> joint.parent_interframe
+    P_frame
+    >>> joint.child_interframe
+    C_frame
+    >>> joint.coordinates
+    Matrix([
+    [q0_PC(t)],
+    [q1_PC(t)],
+    [q2_PC(t)]])
+    >>> joint.speeds
+    Matrix([
+    [u0_PC(t)],
+    [u1_PC(t)],
+    [u2_PC(t)]])
+    >>> child.frame.ang_vel_in(parent.frame).to_matrix(child.frame)
+    Matrix([
+    [ u0_PC(t)*cos(q1_PC(t))*cos(q2_PC(t)) + u1_PC(t)*sin(q2_PC(t))],
+    [-u0_PC(t)*sin(q2_PC(t))*cos(q1_PC(t)) + u1_PC(t)*cos(q2_PC(t))],
+    [                             u0_PC(t)*sin(q1_PC(t)) + u2_PC(t)]])
+    >>> child.frame.x.to_matrix(parent.frame)
+    Matrix([
+    [                                            cos(q1_PC(t))*cos(q2_PC(t))],
+    [sin(q0_PC(t))*sin(q1_PC(t))*cos(q2_PC(t)) + sin(q2_PC(t))*cos(q0_PC(t))],
+    [sin(q0_PC(t))*sin(q2_PC(t)) - sin(q1_PC(t))*cos(q0_PC(t))*cos(q2_PC(t))]])
+    >>> joint.child_point.pos_from(joint.parent_point)
+    0
+
+    To further demonstrate the use of the spherical joint, the kinematics of a
+    spherical joint with a ZXZ rotation can be created as follows.
+
+    >>> from sympy import symbols
+    >>> from sympy.physics.mechanics import RigidBody, SphericalJoint
+    >>> l1 = symbols('l1')
+
+    First create bodies to represent the fixed floor and a pendulum bob.
+
+    >>> floor = RigidBody('F')
+    >>> bob = RigidBody('B')
+
+    The joint will connect the bob to the floor, with the joint located at a
+    distance of ``l1`` from the child's center of mass and the rotation set to a
+    body-fixed ZXZ rotation.
+
+    >>> joint = SphericalJoint('S', floor, bob, child_point=l1 * bob.y,
+    ...                        rot_type='body', rot_order='ZXZ')
+
+    Now that the joint is established, the kinematics of the connected body can
+    be accessed.
+
+    The position of the bob's masscenter is found with:
+
+    >>> bob.masscenter.pos_from(floor.masscenter)
+    - l1*B_frame.y
+
+    The angular velocities of the pendulum link can be computed with respect to
+    the floor.
+
+    >>> bob.frame.ang_vel_in(floor.frame).to_matrix(
+    ...     floor.frame).simplify()
+    Matrix([
+    [u1_S(t)*cos(q0_S(t)) + u2_S(t)*sin(q0_S(t))*sin(q1_S(t))],
+    [u1_S(t)*sin(q0_S(t)) - u2_S(t)*sin(q1_S(t))*cos(q0_S(t))],
+    [                          u0_S(t) + u2_S(t)*cos(q1_S(t))]])
+
+    Finally, the linear velocity of the bob's center of mass can be computed.
+
+    >>> bob.masscenter.vel(floor.frame).to_matrix(bob.frame)
+    Matrix([
+    [                           l1*(u0_S(t)*cos(q1_S(t)) + u2_S(t))],
+    [                                                             0],
+    [-l1*(u0_S(t)*sin(q1_S(t))*sin(q2_S(t)) + u1_S(t)*cos(q2_S(t)))]])
+
+    """
+    def __init__(self, name, parent, child, coordinates=None, speeds=None,
+                 parent_point=None, child_point=None, parent_interframe=None,
+                 child_interframe=None, rot_type='BODY', amounts=None,
+                 rot_order=123):
+        self._rot_type = rot_type
+        self._amounts = amounts
+        self._rot_order = rot_order
+        super().__init__(name, parent, child, coordinates, speeds,
+                         parent_point, child_point,
+                         parent_interframe=parent_interframe,
+                         child_interframe=child_interframe)
+
+    def __str__(self):
+        return (f'SphericalJoint: {self.name}  parent: {self.parent}  '
+                f'child: {self.child}')
+
+    def _generate_coordinates(self, coordinates):
+        return self._fill_coordinate_list(coordinates, 3, 'q')
+
+    def _generate_speeds(self, speeds):
+        return self._fill_coordinate_list(speeds, len(self.coordinates), 'u')
+
+    def _orient_frames(self):
+        supported_rot_types = ('BODY', 'SPACE')
+        if self._rot_type.upper() not in supported_rot_types:
+            raise NotImplementedError(
+                f'Rotation type "{self._rot_type}" is not implemented. '
+                f'Implemented rotation types are: {supported_rot_types}')
+        amounts = self.coordinates if self._amounts is None else self._amounts
+        self.child_interframe.orient(self.parent_interframe, self._rot_type,
+                                     amounts, self._rot_order)
+
+    def _set_angular_velocity(self):
+        t = dynamicsymbols._t
+        vel = self.child_interframe.ang_vel_in(self.parent_interframe).xreplace(
+            {q.diff(t): u for q, u in zip(self.coordinates, self.speeds)}
+        )
+        self.child_interframe.set_ang_vel(self.parent_interframe, vel)
+
+    def _set_linear_velocity(self):
+        self.child_point.set_pos(self.parent_point, 0)
+        self.parent_point.set_vel(self._parent_frame, 0)
+        self.child_point.set_vel(self._child_frame, 0)
+        self.child.masscenter.v2pt_theory(self.parent_point, self._parent_frame,
+                                          self._child_frame)
+
+
+class WeldJoint(Joint):
+    """Weld Joint.
+
+    .. raw:: html
+        :file: ../../../doc/src/modules/physics/mechanics/api/WeldJoint.svg
+
+    Explanation
+    ===========
+
+    A weld joint is defined such that there is no relative motion between the
+    child and parent bodies. The direction cosine matrix between the attachment
+    frame (``parent_interframe`` and ``child_interframe``) is the identity
+    matrix and the attachment points (``parent_point`` and ``child_point``) are
+    coincident. The page on the joints framework gives a more detailed
+    explanation of the intermediate frames.
+
+    Parameters
+    ==========
+
+    name : string
+        A unique name for the joint.
+    parent : Particle or RigidBody or Body
+        The parent body of joint.
+    child : Particle or RigidBody or Body
+        The child body of joint.
+    parent_point : Point or Vector, optional
+        Attachment point where the joint is fixed to the parent body. If a
+        vector is provided, then the attachment point is computed by adding the
+        vector to the body's mass center. The default value is the parent's mass
+        center.
+    child_point : Point or Vector, optional
+        Attachment point where the joint is fixed to the child body. If a
+        vector is provided, then the attachment point is computed by adding the
+        vector to the body's mass center. The default value is the child's mass
+        center.
+    parent_interframe : ReferenceFrame, optional
+        Intermediate frame of the parent body with respect to which the joint
+        transformation is formulated. If a Vector is provided then an interframe
+        is created which aligns its X axis with the given vector. The default
+        value is the parent's own frame.
+    child_interframe : ReferenceFrame, optional
+        Intermediate frame of the child body with respect to which the joint
+        transformation is formulated. If a Vector is provided then an interframe
+        is created which aligns its X axis with the given vector. The default
+        value is the child's own frame.
+
+    Attributes
+    ==========
+
+    name : string
+        The joint's name.
+    parent : Particle or RigidBody or Body
+        The joint's parent body.
+    child : Particle or RigidBody or Body
+        The joint's child body.
+    coordinates : Matrix
+        Matrix of the joint's generalized coordinates. The default value is
+        ``dynamicsymbols(f'q_{joint.name}')``.
+    speeds : Matrix
+        Matrix of the joint's generalized speeds. The default value is
+        ``dynamicsymbols(f'u_{joint.name}')``.
+    parent_point : Point
+        Attachment point where the joint is fixed to the parent body.
+    child_point : Point
+        Attachment point where the joint is fixed to the child body.
+    parent_interframe : ReferenceFrame
+        Intermediate frame of the parent body with respect to which the joint
+        transformation is formulated.
+    child_interframe : ReferenceFrame
+        Intermediate frame of the child body with respect to which the joint
+        transformation is formulated.
+    kdes : Matrix
+        Kinematical differential equations of the joint.
+
+    Examples
+    =========
+
+    A single weld joint is created from two bodies and has the following basic
+    attributes:
+
+    >>> from sympy.physics.mechanics import RigidBody, WeldJoint
+    >>> parent = RigidBody('P')
+    >>> parent
+    P
+    >>> child = RigidBody('C')
+    >>> child
+    C
+    >>> joint = WeldJoint('PC', parent, child)
+    >>> joint
+    WeldJoint: PC  parent: P  child: C
+    >>> joint.name
+    'PC'
+    >>> joint.parent
+    P
+    >>> joint.child
+    C
+    >>> joint.parent_point
+    P_masscenter
+    >>> joint.child_point
+    C_masscenter
+    >>> joint.coordinates
+    Matrix(0, 0, [])
+    >>> joint.speeds
+    Matrix(0, 0, [])
+    >>> child.frame.ang_vel_in(parent.frame)
+    0
+    >>> child.frame.dcm(parent.frame)
+    Matrix([
+    [1, 0, 0],
+    [0, 1, 0],
+    [0, 0, 1]])
+    >>> joint.child_point.pos_from(joint.parent_point)
+    0
+
+    To further demonstrate the use of the weld joint, two relatively-fixed
+    bodies rotated by a quarter turn about the Y axis can be created as follows:
+
+    >>> from sympy import symbols, pi
+    >>> from sympy.physics.mechanics import ReferenceFrame, RigidBody, WeldJoint
+    >>> l1, l2 = symbols('l1 l2')
+
+    First create the bodies to represent the parent and rotated child body.
+
+    >>> parent = RigidBody('P')
+    >>> child = RigidBody('C')
+
+    Next the intermediate frame specifying the fixed rotation with respect to
+    the parent can be created.
+
+    >>> rotated_frame = ReferenceFrame('Pr')
+    >>> rotated_frame.orient_axis(parent.frame, parent.y, pi / 2)
+
+    The weld between the parent body and child body is located at a distance
+    ``l1`` from the parent's center of mass in the X direction and ``l2`` from
+    the child's center of mass in the child's negative X direction.
+
+    >>> weld = WeldJoint('weld', parent, child, parent_point=l1 * parent.x,
+    ...                  child_point=-l2 * child.x,
+    ...                  parent_interframe=rotated_frame)
+
+    Now that the joint has been established, the kinematics of the bodies can be
+    accessed. The direction cosine matrix of the child body with respect to the
+    parent can be found:
+
+    >>> child.frame.dcm(parent.frame)
+    Matrix([
+    [0, 0, -1],
+    [0, 1,  0],
+    [1, 0,  0]])
+
+    As can also been seen from the direction cosine matrix, the parent X axis is
+    aligned with the child's Z axis:
+    >>> parent.x == child.z
+    True
+
+    The position of the child's center of mass with respect to the parent's
+    center of mass can be found with:
+
+    >>> child.masscenter.pos_from(parent.masscenter)
+    l1*P_frame.x + l2*C_frame.x
+
+    The angular velocity of the child with respect to the parent is 0 as one
+    would expect.
+
+    >>> child.frame.ang_vel_in(parent.frame)
+    0
+
+    """
+
+    def __init__(self, name, parent, child, parent_point=None, child_point=None,
+                 parent_interframe=None, child_interframe=None):
+        super().__init__(name, parent, child, [], [], parent_point,
+                         child_point, parent_interframe=parent_interframe,
+                         child_interframe=child_interframe)
+        self._kdes = Matrix(1, 0, []).T  # Removes stackability problems #10770
+
+    def __str__(self):
+        return (f'WeldJoint: {self.name}  parent: {self.parent}  '
+                f'child: {self.child}')
+
+    def _generate_coordinates(self, coordinate):
+        return Matrix()
+
+    def _generate_speeds(self, speed):
+        return Matrix()
+
+    def _orient_frames(self):
+        self.child_interframe.orient_axis(self.parent_interframe,
+                                          self.parent_interframe.x, 0)
+
+    def _set_angular_velocity(self):
+        self.child_interframe.set_ang_vel(self.parent_interframe, 0)
+
+    def _set_linear_velocity(self):
+        self.child_point.set_pos(self.parent_point, 0)
+        self.parent_point.set_vel(self._parent_frame, 0)
+        self.child_point.set_vel(self._child_frame, 0)
+        self.child.masscenter.set_vel(self._parent_frame, 0)

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/jointsmethod.py

@@ -0,0 +1,318 @@
+from sympy.physics.mechanics import (Body, Lagrangian, KanesMethod, LagrangesMethod,
+                                    RigidBody, Particle)
+from sympy.physics.mechanics.body_base import BodyBase
+from sympy.physics.mechanics.method import _Methods
+from sympy import Matrix
+from sympy.utilities.exceptions import sympy_deprecation_warning
+
+__all__ = ['JointsMethod']
+
+
+class JointsMethod(_Methods):
+    """Method for formulating the equations of motion using a set of interconnected bodies with joints.
+
+    .. deprecated:: 1.13
+        The JointsMethod class is deprecated. Its functionality has been
+        replaced by the new :class:`~.System` class.
+
+    Parameters
+    ==========
+
+    newtonion : Body or ReferenceFrame
+        The newtonion(inertial) frame.
+    *joints : Joint
+        The joints in the system
+
+    Attributes
+    ==========
+
+    q, u : iterable
+        Iterable of the generalized coordinates and speeds
+    bodies : iterable
+        Iterable of Body objects in the system.
+    loads : iterable
+        Iterable of (Point, vector) or (ReferenceFrame, vector) tuples
+        describing the forces on the system.
+    mass_matrix : Matrix, shape(n, n)
+        The system's mass matrix
+    forcing : Matrix, shape(n, 1)
+        The system's forcing vector
+    mass_matrix_full : Matrix, shape(2*n, 2*n)
+        The "mass matrix" for the u's and q's
+    forcing_full : Matrix, shape(2*n, 1)
+        The "forcing vector" for the u's and q's
+    method : KanesMethod or Lagrange's method
+        Method's object.
+    kdes : iterable
+        Iterable of kde in they system.
+
+    Examples
+    ========
+
+    As Body and JointsMethod have been deprecated, the following examples are
+    for illustrative purposes only. The functionality of Body is fully captured
+    by :class:`~.RigidBody` and :class:`~.Particle` and the functionality of
+    JointsMethod is fully captured by :class:`~.System`. To ignore the
+    deprecation warning we can use the ignore_warnings context manager.
+
+    >>> from sympy.utilities.exceptions import ignore_warnings
+
+    This is a simple example for a one degree of freedom translational
+    spring-mass-damper.
+
+    >>> from sympy import symbols
+    >>> from sympy.physics.mechanics import Body, JointsMethod, PrismaticJoint
+    >>> from sympy.physics.vector import dynamicsymbols
+    >>> c, k = symbols('c k')
+    >>> x, v = dynamicsymbols('x v')
+    >>> with ignore_warnings(DeprecationWarning):
+    ...     wall = Body('W')
+    ...     body = Body('B')
+    >>> J = PrismaticJoint('J', wall, body, coordinates=x, speeds=v)
+    >>> wall.apply_force(c*v*wall.x, reaction_body=body)
+    >>> wall.apply_force(k*x*wall.x, reaction_body=body)
+    >>> with ignore_warnings(DeprecationWarning):
+    ...     method = JointsMethod(wall, J)
+    >>> method.form_eoms()
+    Matrix([[-B_mass*Derivative(v(t), t) - c*v(t) - k*x(t)]])
+    >>> M = method.mass_matrix_full
+    >>> F = method.forcing_full
+    >>> rhs = M.LUsolve(F)
+    >>> rhs
+    Matrix([
+    [                     v(t)],
+    [(-c*v(t) - k*x(t))/B_mass]])
+
+    Notes
+    =====
+
+    ``JointsMethod`` currently only works with systems that do not have any
+    configuration or motion constraints.
+
+    """
+
+    def __init__(self, newtonion, *joints):
+        sympy_deprecation_warning(
+            """
+            The JointsMethod class is deprecated.
+            Its functionality has been replaced by the new System class.
+            """,
+            deprecated_since_version="1.13",
+            active_deprecations_target="deprecated-mechanics-jointsmethod"
+        )
+        if isinstance(newtonion, BodyBase):
+            self.frame = newtonion.frame
+        else:
+            self.frame = newtonion
+
+        self._joints = joints
+        self._bodies = self._generate_bodylist()
+        self._loads = self._generate_loadlist()
+        self._q = self._generate_q()
+        self._u = self._generate_u()
+        self._kdes = self._generate_kdes()
+
+        self._method = None
+
+    @property
+    def bodies(self):
+        """List of bodies in they system."""
+        return self._bodies
+
+    @property
+    def loads(self):
+        """List of loads on the system."""
+        return self._loads
+
+    @property
+    def q(self):
+        """List of the generalized coordinates."""
+        return self._q
+
+    @property
+    def u(self):
+        """List of the generalized speeds."""
+        return self._u
+
+    @property
+    def kdes(self):
+        """List of the generalized coordinates."""
+        return self._kdes
+
+    @property
+    def forcing_full(self):
+        """The "forcing vector" for the u's and q's."""
+        return self.method.forcing_full
+
+    @property
+    def mass_matrix_full(self):
+        """The "mass matrix" for the u's and q's."""
+        return self.method.mass_matrix_full
+
+    @property
+    def mass_matrix(self):
+        """The system's mass matrix."""
+        return self.method.mass_matrix
+
+    @property
+    def forcing(self):
+        """The system's forcing vector."""
+        return self.method.forcing
+
+    @property
+    def method(self):
+        """Object of method used to form equations of systems."""
+        return self._method
+
+    def _generate_bodylist(self):
+        bodies = []
+        for joint in self._joints:
+            if joint.child not in bodies:
+                bodies.append(joint.child)
+            if joint.parent not in bodies:
+                bodies.append(joint.parent)
+        return bodies
+
+    def _generate_loadlist(self):
+        load_list = []
+        for body in self.bodies:
+            if isinstance(body, Body):
+                load_list.extend(body.loads)
+        return load_list
+
+    def _generate_q(self):
+        q_ind = []
+        for joint in self._joints:
+            for coordinate in joint.coordinates:
+                if coordinate in q_ind:
+                    raise ValueError('Coordinates of joints should be unique.')
+                q_ind.append(coordinate)
+        return Matrix(q_ind)
+
+    def _generate_u(self):
+        u_ind = []
+        for joint in self._joints:
+            for speed in joint.speeds:
+                if speed in u_ind:
+                    raise ValueError('Speeds of joints should be unique.')
+                u_ind.append(speed)
+        return Matrix(u_ind)
+
+    def _generate_kdes(self):
+        kd_ind = Matrix(1, 0, []).T
+        for joint in self._joints:
+            kd_ind = kd_ind.col_join(joint.kdes)
+        return kd_ind
+
+    def _convert_bodies(self):
+        # Convert `Body` to `Particle` and `RigidBody`
+        bodylist = []
+        for body in self.bodies:
+            if not isinstance(body, Body):
+                bodylist.append(body)
+                continue
+            if body.is_rigidbody:
+                rb = RigidBody(body.name, body.masscenter, body.frame, body.mass,
+                    (body.central_inertia, body.masscenter))
+                rb.potential_energy = body.potential_energy
+                bodylist.append(rb)
+            else:
+                part = Particle(body.name, body.masscenter, body.mass)
+                part.potential_energy = body.potential_energy
+                bodylist.append(part)
+        return bodylist
+
+    def form_eoms(self, method=KanesMethod):
+        """Method to form system's equation of motions.
+
+        Parameters
+        ==========
+
+        method : Class
+            Class name of method.
+
+        Returns
+        ========
+
+        Matrix
+            Vector of equations of motions.
+
+        Examples
+        ========
+
+        As Body and JointsMethod have been deprecated, the following examples
+        are for illustrative purposes only. The functionality of Body is fully
+        captured by :class:`~.RigidBody` and :class:`~.Particle` and the
+        functionality of JointsMethod is fully captured by :class:`~.System`. To
+        ignore the deprecation warning we can use the ignore_warnings context
+        manager.
+
+        >>> from sympy.utilities.exceptions import ignore_warnings
+
+        This is a simple example for a one degree of freedom translational
+        spring-mass-damper.
+
+        >>> from sympy import S, symbols
+        >>> from sympy.physics.mechanics import LagrangesMethod, dynamicsymbols, Body
+        >>> from sympy.physics.mechanics import PrismaticJoint, JointsMethod
+        >>> q = dynamicsymbols('q')
+        >>> qd = dynamicsymbols('q', 1)
+        >>> m, k, b = symbols('m k b')
+        >>> with ignore_warnings(DeprecationWarning):
+        ...     wall = Body('W')
+        ...     part = Body('P', mass=m)
+        >>> part.potential_energy = k * q**2 / S(2)
+        >>> J = PrismaticJoint('J', wall, part, coordinates=q, speeds=qd)
+        >>> wall.apply_force(b * qd * wall.x, reaction_body=part)
+        >>> with ignore_warnings(DeprecationWarning):
+        ...     method = JointsMethod(wall, J)
+        >>> method.form_eoms(LagrangesMethod)
+        Matrix([[b*Derivative(q(t), t) + k*q(t) + m*Derivative(q(t), (t, 2))]])
+
+        We can also solve for the states using the 'rhs' method.
+
+        >>> method.rhs()
+        Matrix([
+        [                Derivative(q(t), t)],
+        [(-b*Derivative(q(t), t) - k*q(t))/m]])
+
+        """
+
+        bodylist = self._convert_bodies()
+        if issubclass(method, LagrangesMethod): #LagrangesMethod or similar
+            L = Lagrangian(self.frame, *bodylist)
+            self._method = method(L, self.q, self.loads, bodylist, self.frame)
+        else: #KanesMethod or similar
+            self._method = method(self.frame, q_ind=self.q, u_ind=self.u, kd_eqs=self.kdes,
+                                    forcelist=self.loads, bodies=bodylist)
+        soln = self.method._form_eoms()
+        return soln
+
+    def rhs(self, inv_method=None):
+        """Returns equations that can be solved numerically.
+
+        Parameters
+        ==========
+
+        inv_method : str
+            The specific sympy inverse matrix calculation method to use. For a
+            list of valid methods, see
+            :meth:`~sympy.matrices.matrixbase.MatrixBase.inv`
+
+        Returns
+        ========
+
+        Matrix
+            Numerically solvable equations.
+
+        See Also
+        ========
+
+        sympy.physics.mechanics.kane.KanesMethod.rhs:
+            KanesMethod's rhs function.
+        sympy.physics.mechanics.lagrange.LagrangesMethod.rhs:
+            LagrangesMethod's rhs function.
+
+        """
+
+        return self.method.rhs(inv_method=inv_method)

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/kane.py

@@ -0,0 +1,860 @@
+from sympy import zeros, Matrix, diff, eye
+from sympy.core.sorting import default_sort_key
+from sympy.physics.vector import (ReferenceFrame, dynamicsymbols,
+                                  partial_velocity)
+from sympy.physics.mechanics.method import _Methods
+from sympy.physics.mechanics.particle import Particle
+from sympy.physics.mechanics.rigidbody import RigidBody
+from sympy.physics.mechanics.functions import (msubs, find_dynamicsymbols,
+                                               _f_list_parser,
+                                               _validate_coordinates,
+                                               _parse_linear_solver)
+from sympy.physics.mechanics.linearize import Linearizer
+from sympy.utilities.iterables import iterable
+
+__all__ = ['KanesMethod']
+
+
+class KanesMethod(_Methods):
+    r"""Kane's method object.
+
+    Explanation
+    ===========
+
+    This object is used to do the "book-keeping" as you go through and form
+    equations of motion in the way Kane presents in:
+    Kane, T., Levinson, D. Dynamics Theory and Applications. 1985 McGraw-Hill
+
+    The attributes are for equations in the form [M] udot = forcing.
+
+    Attributes
+    ==========
+
+    q, u : Matrix
+        Matrices of the generalized coordinates and speeds
+    bodies : iterable
+        Iterable of Particle and RigidBody objects in the system.
+    loads : iterable
+        Iterable of (Point, vector) or (ReferenceFrame, vector) tuples
+        describing the forces on the system.
+    auxiliary_eqs : Matrix
+        If applicable, the set of auxiliary Kane's
+        equations used to solve for non-contributing
+        forces.
+    mass_matrix : Matrix
+        The system's dynamics mass matrix: [k_d; k_dnh]
+    forcing : Matrix
+        The system's dynamics forcing vector: -[f_d; f_dnh]
+    mass_matrix_kin : Matrix
+        The "mass matrix" for kinematic differential equations: k_kqdot
+    forcing_kin : Matrix
+        The forcing vector for kinematic differential equations: -(k_ku*u + f_k)
+    mass_matrix_full : Matrix
+        The "mass matrix" for the u's and q's with dynamics and kinematics
+    forcing_full : Matrix
+        The "forcing vector" for the u's and q's with dynamics and kinematics
+
+    Parameters
+    ==========
+
+    frame : ReferenceFrame
+        The inertial reference frame for the system.
+    q_ind : iterable of dynamicsymbols
+        Independent generalized coordinates.
+    u_ind : iterable of dynamicsymbols
+        Independent generalized speeds.
+    kd_eqs : iterable of Expr, optional
+        Kinematic differential equations, which linearly relate the generalized
+        speeds to the time-derivatives of the generalized coordinates.
+    q_dependent : iterable of dynamicsymbols, optional
+        Dependent generalized coordinates.
+    configuration_constraints : iterable of Expr, optional
+        Constraints on the system's configuration, i.e. holonomic constraints.
+    u_dependent : iterable of dynamicsymbols, optional
+        Dependent generalized speeds.
+    velocity_constraints : iterable of Expr, optional
+        Constraints on the system's velocity, i.e. the combination of the
+        nonholonomic constraints and the time-derivative of the holonomic
+        constraints.
+    acceleration_constraints : iterable of Expr, optional
+        Constraints on the system's acceleration, by default these are the
+        time-derivative of the velocity constraints.
+    u_auxiliary : iterable of dynamicsymbols, optional
+        Auxiliary generalized speeds.
+    bodies : iterable of Particle and/or RigidBody, optional
+        The particles and rigid bodies in the system.
+    forcelist : iterable of tuple[Point | ReferenceFrame, Vector], optional
+        Forces and torques applied on the system.
+    explicit_kinematics : bool
+        Boolean whether the mass matrices and forcing vectors should use the
+        explicit form (default) or implicit form for kinematics.
+        See the notes for more details.
+    kd_eqs_solver : str, callable
+        Method used to solve the kinematic differential equations. If a string
+        is supplied, it should be a valid method that can be used with the
+        :meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is
+        supplied, it should have the format ``f(A, rhs)``, where it solves the
+        equations and returns the solution. The default utilizes LU solve. See
+        the notes for more information.
+    constraint_solver : str, callable
+        Method used to solve the velocity constraints. If a string is
+        supplied, it should be a valid method that can be used with the
+        :meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is
+        supplied, it should have the format ``f(A, rhs)``, where it solves the
+        equations and returns the solution. The default utilizes LU solve. See
+        the notes for more information.
+
+    Notes
+    =====
+
+    The mass matrices and forcing vectors related to kinematic equations
+    are given in the explicit form by default. In other words, the kinematic
+    mass matrix is $\mathbf{k_{k\dot{q}}} = \mathbf{I}$.
+    In order to get the implicit form of those matrices/vectors, you can set the
+    ``explicit_kinematics`` attribute to ``False``. So $\mathbf{k_{k\dot{q}}}$
+    is not necessarily an identity matrix. This can provide more compact
+    equations for non-simple kinematics.
+
+    Two linear solvers can be supplied to ``KanesMethod``: one for solving the
+    kinematic differential equations and one to solve the velocity constraints.
+    Both of these sets of equations can be expressed as a linear system ``Ax = rhs``,
+    which have to be solved in order to obtain the equations of motion.
+
+    The default solver ``'LU'``, which stands for LU solve, results relatively low
+    number of operations. The weakness of this method is that it can result in zero
+    division errors.
+
+    If zero divisions are encountered, a possible solver which may solve the problem
+    is ``"CRAMER"``. This method uses Cramer's rule to solve the system. This method
+    is slower and results in more operations than the default solver. However it only
+    uses a single division by default per entry of the solution.
+
+    While a valid list of solvers can be found at
+    :meth:`sympy.matrices.matrixbase.MatrixBase.solve`, it is also possible to supply a
+    `callable`. This way it is possible to use a different solver routine. If the
+    kinematic differential equations are not too complex it can be worth it to simplify
+    the solution by using ``lambda A, b: simplify(Matrix.LUsolve(A, b))``. Another
+    option solver one may use is :func:`sympy.solvers.solveset.linsolve`. This can be
+    done using `lambda A, b: tuple(linsolve((A, b)))[0]`, where we select the first
+    solution as our system should have only one unique solution.
+
+    Examples
+    ========
+
+    This is a simple example for a one degree of freedom translational
+    spring-mass-damper.
+
+    In this example, we first need to do the kinematics.
+    This involves creating generalized speeds and coordinates and their
+    derivatives.
+    Then we create a point and set its velocity in a frame.
+
+        >>> from sympy import symbols
+        >>> from sympy.physics.mechanics import dynamicsymbols, ReferenceFrame
+        >>> from sympy.physics.mechanics import Point, Particle, KanesMethod
+        >>> q, u = dynamicsymbols('q u')
+        >>> qd, ud = dynamicsymbols('q u', 1)
+        >>> m, c, k = symbols('m c k')
+        >>> N = ReferenceFrame('N')
+        >>> P = Point('P')
+        >>> P.set_vel(N, u * N.x)
+
+    Next we need to arrange/store information in the way that KanesMethod
+    requires. The kinematic differential equations should be an iterable of
+    expressions. A list of forces/torques must be constructed, where each entry
+    in the list is a (Point, Vector) or (ReferenceFrame, Vector) tuple, where
+    the Vectors represent the Force or Torque.
+    Next a particle needs to be created, and it needs to have a point and mass
+    assigned to it.
+    Finally, a list of all bodies and particles needs to be created.
+
+        >>> kd = [qd - u]
+        >>> FL = [(P, (-k * q - c * u) * N.x)]
+        >>> pa = Particle('pa', P, m)
+        >>> BL = [pa]
+
+    Finally we can generate the equations of motion.
+    First we create the KanesMethod object and supply an inertial frame,
+    coordinates, generalized speeds, and the kinematic differential equations.
+    Additional quantities such as configuration and motion constraints,
+    dependent coordinates and speeds, and auxiliary speeds are also supplied
+    here (see the online documentation).
+    Next we form FR* and FR to complete: Fr + Fr* = 0.
+    We have the equations of motion at this point.
+    It makes sense to rearrange them though, so we calculate the mass matrix and
+    the forcing terms, for E.o.M. in the form: [MM] udot = forcing, where MM is
+    the mass matrix, udot is a vector of the time derivatives of the
+    generalized speeds, and forcing is a vector representing "forcing" terms.
+
+        >>> KM = KanesMethod(N, q_ind=[q], u_ind=[u], kd_eqs=kd)
+        >>> (fr, frstar) = KM.kanes_equations(BL, FL)
+        >>> MM = KM.mass_matrix
+        >>> forcing = KM.forcing
+        >>> rhs = MM.inv() * forcing
+        >>> rhs
+        Matrix([[(-c*u(t) - k*q(t))/m]])
+        >>> KM.linearize(A_and_B=True)[0]
+        Matrix([
+        [   0,    1],
+        [-k/m, -c/m]])
+
+    Please look at the documentation pages for more information on how to
+    perform linearization and how to deal with dependent coordinates & speeds,
+    and how do deal with bringing non-contributing forces into evidence.
+
+    """
+
+    def __init__(self, frame, q_ind, u_ind, kd_eqs=None, q_dependent=None,
+                 configuration_constraints=None, u_dependent=None,
+                 velocity_constraints=None, acceleration_constraints=None,
+                 u_auxiliary=None, bodies=None, forcelist=None,
+                 explicit_kinematics=True, kd_eqs_solver='LU',
+                 constraint_solver='LU'):
+
+        """Please read the online documentation. """
+        if not q_ind:
+            q_ind = [dynamicsymbols('dummy_q')]
+            kd_eqs = [dynamicsymbols('dummy_kd')]
+
+        if not isinstance(frame, ReferenceFrame):
+            raise TypeError('An inertial ReferenceFrame must be supplied')
+        self._inertial = frame
+
+        self._fr = None
+        self._frstar = None
+
+        self._forcelist = forcelist
+        self._bodylist = bodies
+
+        self.explicit_kinematics = explicit_kinematics
+        self._constraint_solver = constraint_solver
+        self._initialize_vectors(q_ind, q_dependent, u_ind, u_dependent,
+                u_auxiliary)
+        _validate_coordinates(self.q, self.u)
+        self._initialize_kindiffeq_matrices(kd_eqs, kd_eqs_solver)
+        self._initialize_constraint_matrices(
+            configuration_constraints, velocity_constraints,
+            acceleration_constraints, constraint_solver)
+
+    def _initialize_vectors(self, q_ind, q_dep, u_ind, u_dep, u_aux):
+        """Initialize the coordinate and speed vectors."""
+
+        none_handler = lambda x: Matrix(x) if x else Matrix()
+
+        # Initialize generalized coordinates
+        q_dep = none_handler(q_dep)
+        if not iterable(q_ind):
+            raise TypeError('Generalized coordinates must be an iterable.')
+        if not iterable(q_dep):
+            raise TypeError('Dependent coordinates must be an iterable.')
+        q_ind = Matrix(q_ind)
+        self._qdep = q_dep
+        self._q = Matrix([q_ind, q_dep])
+        self._qdot = self.q.diff(dynamicsymbols._t)
+
+        # Initialize generalized speeds
+        u_dep = none_handler(u_dep)
+        if not iterable(u_ind):
+            raise TypeError('Generalized speeds must be an iterable.')
+        if not iterable(u_dep):
+            raise TypeError('Dependent speeds must be an iterable.')
+        u_ind = Matrix(u_ind)
+        self._udep = u_dep
+        self._u = Matrix([u_ind, u_dep])
+        self._udot = self.u.diff(dynamicsymbols._t)
+        self._uaux = none_handler(u_aux)
+
+    def _initialize_constraint_matrices(self, config, vel, acc, linear_solver='LU'):
+        """Initializes constraint matrices."""
+        linear_solver = _parse_linear_solver(linear_solver)
+        # Define vector dimensions
+        o = len(self.u)
+        m = len(self._udep)
+        p = o - m
+        none_handler = lambda x: Matrix(x) if x else Matrix()
+
+        # Initialize configuration constraints
+        config = none_handler(config)
+        if len(self._qdep) != len(config):
+            raise ValueError('There must be an equal number of dependent '
+                             'coordinates and configuration constraints.')
+        self._f_h = none_handler(config)
+
+        # Initialize velocity and acceleration constraints
+        vel = none_handler(vel)
+        acc = none_handler(acc)
+        if len(vel) != m:
+            raise ValueError('There must be an equal number of dependent '
+                             'speeds and velocity constraints.')
+        if acc and (len(acc) != m):
+            raise ValueError('There must be an equal number of dependent '
+                             'speeds and acceleration constraints.')
+        if vel:
+            u_zero = dict.fromkeys(self.u, 0)
+            udot_zero = dict.fromkeys(self._udot, 0)
+
+            # When calling kanes_equations, another class instance will be
+            # created if auxiliary u's are present. In this case, the
+            # computation of kinetic differential equation matrices will be
+            # skipped as this was computed during the original KanesMethod
+            # object, and the qd_u_map will not be available.
+            if self._qdot_u_map is not None:
+                vel = msubs(vel, self._qdot_u_map)
+
+            self._f_nh = msubs(vel, u_zero)
+            self._k_nh = (vel - self._f_nh).jacobian(self.u)
+            # If no acceleration constraints given, calculate them.
+            if not acc:
+                _f_dnh = (self._k_nh.diff(dynamicsymbols._t) * self.u +
+                          self._f_nh.diff(dynamicsymbols._t))
+                if self._qdot_u_map is not None:
+                    _f_dnh = msubs(_f_dnh, self._qdot_u_map)
+                self._f_dnh = _f_dnh
+                self._k_dnh = self._k_nh
+            else:
+                if self._qdot_u_map is not None:
+                    acc = msubs(acc, self._qdot_u_map)
+                self._f_dnh = msubs(acc, udot_zero)
+                self._k_dnh = (acc - self._f_dnh).jacobian(self._udot)
+
+            # Form of non-holonomic constraints is B*u + C = 0.
+            # We partition B into independent and dependent columns:
+            # Ars is then -B_dep.inv() * B_ind, and it relates dependent speeds
+            # to independent speeds as: udep = Ars*uind, neglecting the C term.
+            B_ind = self._k_nh[:, :p]
+            B_dep = self._k_nh[:, p:o]
+            self._Ars = -linear_solver(B_dep, B_ind)
+        else:
+            self._f_nh = Matrix()
+            self._k_nh = Matrix()
+            self._f_dnh = Matrix()
+            self._k_dnh = Matrix()
+            self._Ars = Matrix()
+
+    def _initialize_kindiffeq_matrices(self, kdeqs, linear_solver='LU'):
+        """Initialize the kinematic differential equation matrices.
+
+        Parameters
+        ==========
+        kdeqs : sequence of sympy expressions
+            Kinematic differential equations in the form of f(u,q',q,t) where
+            f() = 0. The equations have to be linear in the generalized
+            coordinates and generalized speeds.
+
+        """
+        linear_solver = _parse_linear_solver(linear_solver)
+        if kdeqs:
+            if len(self.q) != len(kdeqs):
+                raise ValueError('There must be an equal number of kinematic '
+                                 'differential equations and coordinates.')
+
+            u = self.u
+            qdot = self._qdot
+
+            kdeqs = Matrix(kdeqs)
+
+            u_zero = dict.fromkeys(u, 0)
+            uaux_zero = dict.fromkeys(self._uaux, 0)
+            qdot_zero = dict.fromkeys(qdot, 0)
+
+            # Extract the linear coefficient matrices as per the following
+            # equation:
+            #
+            # k_ku(q,t)*u(t) + k_kqdot(q,t)*q'(t) + f_k(q,t) = 0
+            #
+            k_ku = kdeqs.jacobian(u)
+            k_kqdot = kdeqs.jacobian(qdot)
+            f_k = kdeqs.xreplace(u_zero).xreplace(qdot_zero)
+
+            # The kinematic differential equations should be linear in both q'
+            # and u, so check for u and q' in the components.
+            dy_syms = find_dynamicsymbols(k_ku.row_join(k_kqdot).row_join(f_k))
+            nonlin_vars = [vari for vari in u[:] + qdot[:] if vari in dy_syms]
+            if nonlin_vars:
+                msg = ('The provided kinematic differential equations are '
+                       'nonlinear in {}. They must be linear in the '
+                       'generalized speeds and derivatives of the generalized '
+                       'coordinates.')
+                raise ValueError(msg.format(nonlin_vars))
+
+            self._f_k_implicit = f_k.xreplace(uaux_zero)
+            self._k_ku_implicit = k_ku.xreplace(uaux_zero)
+            self._k_kqdot_implicit = k_kqdot
+
+            # Solve for q'(t) such that the coefficient matrices are now in
+            # this form:
+            #
+            # k_kqdot^-1*k_ku*u(t) + I*q'(t) + k_kqdot^-1*f_k = 0
+            #
+            # NOTE : Solving the kinematic differential equations here is not
+            # necessary and prevents the equations from being provided in fully
+            # implicit form.
+            f_k_explicit = linear_solver(k_kqdot, f_k)
+            k_ku_explicit = linear_solver(k_kqdot, k_ku)
+            self._qdot_u_map = dict(zip(qdot, -(k_ku_explicit*u + f_k_explicit)))
+
+            self._f_k = f_k_explicit.xreplace(uaux_zero)
+            self._k_ku = k_ku_explicit.xreplace(uaux_zero)
+            self._k_kqdot = eye(len(qdot))
+
+        else:
+            self._qdot_u_map = None
+            self._f_k_implicit = self._f_k = Matrix()
+            self._k_ku_implicit = self._k_ku = Matrix()
+            self._k_kqdot_implicit = self._k_kqdot = Matrix()
+
+    def _form_fr(self, fl):
+        """Form the generalized active force."""
+        if fl is not None and (len(fl) == 0 or not iterable(fl)):
+            raise ValueError('Force pairs must be supplied in an '
+                'non-empty iterable or None.')
+
+        N = self._inertial
+        # pull out relevant velocities for constructing partial velocities
+        vel_list, f_list = _f_list_parser(fl, N)
+        vel_list = [msubs(i, self._qdot_u_map) for i in vel_list]
+        f_list = [msubs(i, self._qdot_u_map) for i in f_list]
+
+        # Fill Fr with dot product of partial velocities and forces
+        o = len(self.u)
+        b = len(f_list)
+        FR = zeros(o, 1)
+        partials = partial_velocity(vel_list, self.u, N)
+        for i in range(o):
+            FR[i] = sum(partials[j][i].dot(f_list[j]) for j in range(b))
+
+        # In case there are dependent speeds
+        if self._udep:
+            p = o - len(self._udep)
+            FRtilde = FR[:p, 0]
+            FRold = FR[p:o, 0]
+            FRtilde += self._Ars.T * FRold
+            FR = FRtilde
+
+        self._forcelist = fl
+        self._fr = FR
+        return FR
+
+    def _form_frstar(self, bl):
+        """Form the generalized inertia force."""
+
+        if not iterable(bl):
+            raise TypeError('Bodies must be supplied in an iterable.')
+
+        t = dynamicsymbols._t
+        N = self._inertial
+        # Dicts setting things to zero
+        udot_zero = dict.fromkeys(self._udot, 0)
+        uaux_zero = dict.fromkeys(self._uaux, 0)
+        uauxdot = [diff(i, t) for i in self._uaux]
+        uauxdot_zero = dict.fromkeys(uauxdot, 0)
+        # Dictionary of q' and q'' to u and u'
+        q_ddot_u_map = {k.diff(t): v.diff(t).xreplace(
+            self._qdot_u_map) for (k, v) in self._qdot_u_map.items()}
+        q_ddot_u_map.update(self._qdot_u_map)
+
+        # Fill up the list of partials: format is a list with num elements
+        # equal to number of entries in body list. Each of these elements is a
+        # list - either of length 1 for the translational components of
+        # particles or of length 2 for the translational and rotational
+        # components of rigid bodies. The inner most list is the list of
+        # partial velocities.
+        def get_partial_velocity(body):
+            if isinstance(body, RigidBody):
+                vlist = [body.masscenter.vel(N), body.frame.ang_vel_in(N)]
+            elif isinstance(body, Particle):
+                vlist = [body.point.vel(N),]
+            else:
+                raise TypeError('The body list may only contain either '
+                                'RigidBody or Particle as list elements.')
+            v = [msubs(vel, self._qdot_u_map) for vel in vlist]
+            return partial_velocity(v, self.u, N)
+        partials = [get_partial_velocity(body) for body in bl]
+
+        # Compute fr_star in two components:
+        # fr_star = -(MM*u' + nonMM)
+        o = len(self.u)
+        MM = zeros(o, o)
+        nonMM = zeros(o, 1)
+        zero_uaux = lambda expr: msubs(expr, uaux_zero)
+        zero_udot_uaux = lambda expr: msubs(msubs(expr, udot_zero), uaux_zero)
+        for i, body in enumerate(bl):
+            if isinstance(body, RigidBody):
+                M = zero_uaux(body.mass)
+                I = zero_uaux(body.central_inertia)
+                vel = zero_uaux(body.masscenter.vel(N))
+                omega = zero_uaux(body.frame.ang_vel_in(N))
+                acc = zero_udot_uaux(body.masscenter.acc(N))
+                inertial_force = (M.diff(t) * vel + M * acc)
+                inertial_torque = zero_uaux((I.dt(body.frame).dot(omega)) +
+                    msubs(I.dot(body.frame.ang_acc_in(N)), udot_zero) +
+                    (omega.cross(I.dot(omega))))
+                for j in range(o):
+                    tmp_vel = zero_uaux(partials[i][0][j])
+                    tmp_ang = zero_uaux(I.dot(partials[i][1][j]))
+                    for k in range(o):
+                        # translational
+                        MM[j, k] += M*tmp_vel.dot(partials[i][0][k])
+                        # rotational
+                        MM[j, k] += tmp_ang.dot(partials[i][1][k])
+                    nonMM[j] += inertial_force.dot(partials[i][0][j])
+                    nonMM[j] += inertial_torque.dot(partials[i][1][j])
+            else:
+                M = zero_uaux(body.mass)
+                vel = zero_uaux(body.point.vel(N))
+                acc = zero_udot_uaux(body.point.acc(N))
+                inertial_force = (M.diff(t) * vel + M * acc)
+                for j in range(o):
+                    temp = zero_uaux(partials[i][0][j])
+                    for k in range(o):
+                        MM[j, k] += M*temp.dot(partials[i][0][k])
+                    nonMM[j] += inertial_force.dot(partials[i][0][j])
+        # Compose fr_star out of MM and nonMM
+        MM = zero_uaux(msubs(MM, q_ddot_u_map))
+        nonMM = msubs(msubs(nonMM, q_ddot_u_map),
+                udot_zero, uauxdot_zero, uaux_zero)
+        fr_star = -(MM * msubs(Matrix(self._udot), uauxdot_zero) + nonMM)
+
+        # If there are dependent speeds, we need to find fr_star_tilde
+        if self._udep:
+            p = o - len(self._udep)
+            fr_star_ind = fr_star[:p, 0]
+            fr_star_dep = fr_star[p:o, 0]
+            fr_star = fr_star_ind + (self._Ars.T * fr_star_dep)
+            # Apply the same to MM
+            MMi = MM[:p, :]
+            MMd = MM[p:o, :]
+            MM = MMi + (self._Ars.T * MMd)
+            # Apply the same to nonMM
+            nonMM = nonMM[:p, :] + (self._Ars.T * nonMM[p:o, :])
+
+        self._bodylist = bl
+        self._frstar = fr_star
+        self._k_d = MM
+        self._f_d = -(self._fr - nonMM)
+        return fr_star
+
+    def to_linearizer(self, linear_solver='LU'):
+        """Returns an instance of the Linearizer class, initiated from the
+        data in the KanesMethod class. This may be more desirable than using
+        the linearize class method, as the Linearizer object will allow more
+        efficient recalculation (i.e. about varying operating points).
+
+        Parameters
+        ==========
+        linear_solver : str, callable
+            Method used to solve the several symbolic linear systems of the
+            form ``A*x=b`` in the linearization process. If a string is
+            supplied, it should be a valid method that can be used with the
+            :meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is
+            supplied, it should have the format ``x = f(A, b)``, where it
+            solves the equations and returns the solution. The default is
+            ``'LU'`` which corresponds to SymPy's ``A.LUsolve(b)``.
+            ``LUsolve()`` is fast to compute but will often result in
+            divide-by-zero and thus ``nan`` results.
+
+        Returns
+        =======
+        Linearizer
+            An instantiated
+            :class:`sympy.physics.mechanics.linearize.Linearizer`.
+
+        """
+
+        if (self._fr is None) or (self._frstar is None):
+            raise ValueError('Need to compute Fr, Fr* first.')
+
+        # Get required equation components. The Kane's method class breaks
+        # these into pieces. Need to reassemble
+        f_c = self._f_h
+        if self._f_nh and self._k_nh:
+            f_v = self._f_nh + self._k_nh*Matrix(self.u)
+        else:
+            f_v = Matrix()
+        if self._f_dnh and self._k_dnh:
+            f_a = self._f_dnh + self._k_dnh*Matrix(self._udot)
+        else:
+            f_a = Matrix()
+        # Dicts to sub to zero, for splitting up expressions
+        u_zero = dict.fromkeys(self.u, 0)
+        ud_zero = dict.fromkeys(self._udot, 0)
+        qd_zero = dict.fromkeys(self._qdot, 0)
+        qd_u_zero = dict.fromkeys(Matrix([self._qdot, self.u]), 0)
+        # Break the kinematic differential eqs apart into f_0 and f_1
+        f_0 = msubs(self._f_k, u_zero) + self._k_kqdot*Matrix(self._qdot)
+        f_1 = msubs(self._f_k, qd_zero) + self._k_ku*Matrix(self.u)
+        # Break the dynamic differential eqs into f_2 and f_3
+        f_2 = msubs(self._frstar, qd_u_zero)
+        f_3 = msubs(self._frstar, ud_zero) + self._fr
+        f_4 = zeros(len(f_2), 1)
+
+        # Get the required vector components
+        q = self.q
+        u = self.u
+        if self._qdep:
+            q_i = q[:-len(self._qdep)]
+        else:
+            q_i = q
+        q_d = self._qdep
+        if self._udep:
+            u_i = u[:-len(self._udep)]
+        else:
+            u_i = u
+        u_d = self._udep
+
+        # Form dictionary to set auxiliary speeds & their derivatives to 0.
+        uaux = self._uaux
+        uauxdot = uaux.diff(dynamicsymbols._t)
+        uaux_zero = dict.fromkeys(Matrix([uaux, uauxdot]), 0)
+
+        # Checking for dynamic symbols outside the dynamic differential
+        # equations; throws error if there is.
+        sym_list = set(Matrix([q, self._qdot, u, self._udot, uaux, uauxdot]))
+        if any(find_dynamicsymbols(i, sym_list) for i in [self._k_kqdot,
+                self._k_ku, self._f_k, self._k_dnh, self._f_dnh, self._k_d]):
+            raise ValueError('Cannot have dynamicsymbols outside dynamic \
+                             forcing vector.')
+
+        # Find all other dynamic symbols, forming the forcing vector r.
+        # Sort r to make it canonical.
+        r = list(find_dynamicsymbols(msubs(self._f_d, uaux_zero), sym_list))
+        r.sort(key=default_sort_key)
+
+        # Check for any derivatives of variables in r that are also found in r.
+        for i in r:
+            if diff(i, dynamicsymbols._t) in r:
+                raise ValueError('Cannot have derivatives of specified \
+                                 quantities when linearizing forcing terms.')
+        return Linearizer(f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a, q, u, q_i,
+                q_d, u_i, u_d, r, linear_solver=linear_solver)
+
+    # TODO : Remove `new_method` after 1.1 has been released.
+    def linearize(self, *, new_method=None, linear_solver='LU', **kwargs):
+        """ Linearize the equations of motion about a symbolic operating point.
+
+        Parameters
+        ==========
+        new_method
+            Deprecated, does nothing and will be removed.
+        linear_solver : str, callable
+            Method used to solve the several symbolic linear systems of the
+            form ``A*x=b`` in the linearization process. If a string is
+            supplied, it should be a valid method that can be used with the
+            :meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is
+            supplied, it should have the format ``x = f(A, b)``, where it
+            solves the equations and returns the solution. The default is
+            ``'LU'`` which corresponds to SymPy's ``A.LUsolve(b)``.
+            ``LUsolve()`` is fast to compute but will often result in
+            divide-by-zero and thus ``nan`` results.
+        **kwargs
+            Extra keyword arguments are passed to
+            :meth:`sympy.physics.mechanics.linearize.Linearizer.linearize`.
+
+        Explanation
+        ===========
+
+        If kwarg A_and_B is False (default), returns M, A, B, r for the
+        linearized form, M*[q', u']^T = A*[q_ind, u_ind]^T + B*r.
+
+        If kwarg A_and_B is True, returns A, B, r for the linearized form
+        dx = A*x + B*r, where x = [q_ind, u_ind]^T. Note that this is
+        computationally intensive if there are many symbolic parameters. For
+        this reason, it may be more desirable to use the default A_and_B=False,
+        returning M, A, and B. Values may then be substituted in to these
+        matrices, and the state space form found as
+        A = P.T*M.inv()*A, B = P.T*M.inv()*B, where P = Linearizer.perm_mat.
+
+        In both cases, r is found as all dynamicsymbols in the equations of
+        motion that are not part of q, u, q', or u'. They are sorted in
+        canonical form.
+
+        The operating points may be also entered using the ``op_point`` kwarg.
+        This takes a dictionary of {symbol: value}, or a an iterable of such
+        dictionaries. The values may be numeric or symbolic. The more values
+        you can specify beforehand, the faster this computation will run.
+
+        For more documentation, please see the ``Linearizer`` class.
+
+        """
+
+        linearizer = self.to_linearizer(linear_solver=linear_solver)
+        result = linearizer.linearize(**kwargs)
+        return result + (linearizer.r,)
+
+    def kanes_equations(self, bodies=None, loads=None):
+        """ Method to form Kane's equations, Fr + Fr* = 0.
+
+        Explanation
+        ===========
+
+        Returns (Fr, Fr*). In the case where auxiliary generalized speeds are
+        present (say, s auxiliary speeds, o generalized speeds, and m motion
+        constraints) the length of the returned vectors will be o - m + s in
+        length. The first o - m equations will be the constrained Kane's
+        equations, then the s auxiliary Kane's equations. These auxiliary
+        equations can be accessed with the auxiliary_eqs property.
+
+        Parameters
+        ==========
+
+        bodies : iterable
+            An iterable of all RigidBody's and Particle's in the system.
+            A system must have at least one body.
+        loads : iterable
+            Takes in an iterable of (Particle, Vector) or (ReferenceFrame, Vector)
+            tuples which represent the force at a point or torque on a frame.
+            Must be either a non-empty iterable of tuples or None which corresponds
+            to a system with no constraints.
+        """
+        if bodies is None:
+            bodies = self.bodies
+        if  loads is None and self._forcelist is not None:
+            loads = self._forcelist
+        if loads == []:
+            loads = None
+        if not self._k_kqdot:
+            raise AttributeError('Create an instance of KanesMethod with '
+                    'kinematic differential equations to use this method.')
+        fr = self._form_fr(loads)
+        frstar = self._form_frstar(bodies)
+        if self._uaux:
+            if not self._udep:
+                km = KanesMethod(self._inertial, self.q, self._uaux,
+                             u_auxiliary=self._uaux, constraint_solver=self._constraint_solver)
+            else:
+                km = KanesMethod(self._inertial, self.q, self._uaux,
+                        u_auxiliary=self._uaux, u_dependent=self._udep,
+                        velocity_constraints=(self._k_nh * self.u +
+                        self._f_nh),
+                        acceleration_constraints=(self._k_dnh * self._udot +
+                        self._f_dnh),
+                        constraint_solver=self._constraint_solver
+                        )
+            km._qdot_u_map = self._qdot_u_map
+            self._km = km
+            fraux = km._form_fr(loads)
+            frstaraux = km._form_frstar(bodies)
+            self._aux_eq = fraux + frstaraux
+            self._fr = fr.col_join(fraux)
+            self._frstar = frstar.col_join(frstaraux)
+        return (self._fr, self._frstar)
+
+    def _form_eoms(self):
+        fr, frstar = self.kanes_equations(self.bodylist, self.forcelist)
+        return fr + frstar
+
+    def rhs(self, inv_method=None):
+        """Returns the system's equations of motion in first order form. The
+        output is the right hand side of::
+
+           x' = |q'| =: f(q, u, r, p, t)
+                |u'|
+
+        The right hand side is what is needed by most numerical ODE
+        integrators.
+
+        Parameters
+        ==========
+
+        inv_method : str
+            The specific sympy inverse matrix calculation method to use. For a
+            list of valid methods, see
+            :meth:`~sympy.matrices.matrixbase.MatrixBase.inv`
+
+        """
+        rhs = zeros(len(self.q) + len(self.u), 1)
+        kdes = self.kindiffdict()
+        for i, q_i in enumerate(self.q):
+            rhs[i] = kdes[q_i.diff()]
+
+        if inv_method is None:
+            rhs[len(self.q):, 0] = self.mass_matrix.LUsolve(self.forcing)
+        else:
+            rhs[len(self.q):, 0] = (self.mass_matrix.inv(inv_method,
+                                                         try_block_diag=True) *
+                                    self.forcing)
+
+        return rhs
+
+    def kindiffdict(self):
+        """Returns a dictionary mapping q' to u."""
+        if not self._qdot_u_map:
+            raise AttributeError('Create an instance of KanesMethod with '
+                    'kinematic differential equations to use this method.')
+        return self._qdot_u_map
+
+    @property
+    def auxiliary_eqs(self):
+        """A matrix containing the auxiliary equations."""
+        if not self._fr or not self._frstar:
+            raise ValueError('Need to compute Fr, Fr* first.')
+        if not self._uaux:
+            raise ValueError('No auxiliary speeds have been declared.')
+        return self._aux_eq
+
+    @property
+    def mass_matrix_kin(self):
+        r"""The kinematic "mass matrix" $\mathbf{k_{k\dot{q}}}$ of the system."""
+        return self._k_kqdot if self.explicit_kinematics else self._k_kqdot_implicit
+
+    @property
+    def forcing_kin(self):
+        """The kinematic "forcing vector" of the system."""
+        if self.explicit_kinematics:
+            return -(self._k_ku * Matrix(self.u) + self._f_k)
+        else:
+            return -(self._k_ku_implicit * Matrix(self.u) + self._f_k_implicit)
+
+    @property
+    def mass_matrix(self):
+        """The mass matrix of the system."""
+        if not self._fr or not self._frstar:
+            raise ValueError('Need to compute Fr, Fr* first.')
+        return Matrix([self._k_d, self._k_dnh])
+
+    @property
+    def forcing(self):
+        """The forcing vector of the system."""
+        if not self._fr or not self._frstar:
+            raise ValueError('Need to compute Fr, Fr* first.')
+        return -Matrix([self._f_d, self._f_dnh])
+
+    @property
+    def mass_matrix_full(self):
+        """The mass matrix of the system, augmented by the kinematic
+        differential equations in explicit or implicit form."""
+        if not self._fr or not self._frstar:
+            raise ValueError('Need to compute Fr, Fr* first.')
+        o, n = len(self.u), len(self.q)
+        return (self.mass_matrix_kin.row_join(zeros(n, o))).col_join(
+            zeros(o, n).row_join(self.mass_matrix))
+
+    @property
+    def forcing_full(self):
+        """The forcing vector of the system, augmented by the kinematic
+        differential equations in explicit or implicit form."""
+        return Matrix([self.forcing_kin, self.forcing])
+
+    @property
+    def q(self):
+        return self._q
+
+    @property
+    def u(self):
+        return self._u
+
+    @property
+    def bodylist(self):
+        return self._bodylist
+
+    @property
+    def forcelist(self):
+        return self._forcelist
+
+    @property
+    def bodies(self):
+        return self._bodylist
+
+    @property
+    def loads(self):
+        return self._forcelist

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/linearize.py

@@ -0,0 +1,474 @@
+__all__ = ['Linearizer']
+
+from sympy import Matrix, eye, zeros
+from sympy.core.symbol import Dummy
+from sympy.utilities.iterables import flatten
+from sympy.physics.vector import dynamicsymbols
+from sympy.physics.mechanics.functions import msubs, _parse_linear_solver
+
+from collections import namedtuple
+from collections.abc import Iterable
+
+
+class Linearizer:
+    """This object holds the general model form for a dynamic system. This
+    model is used for computing the linearized form of the system, while
+    properly dealing with constraints leading to  dependent coordinates and
+    speeds. The notation and method is described in [1]_.
+
+    Attributes
+    ==========
+
+    f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a : Matrix
+        Matrices holding the general system form.
+    q, u, r : Matrix
+        Matrices holding the generalized coordinates, speeds, and
+        input vectors.
+    q_i, u_i : Matrix
+        Matrices of the independent generalized coordinates and speeds.
+    q_d, u_d : Matrix
+        Matrices of the dependent generalized coordinates and speeds.
+    perm_mat : Matrix
+        Permutation matrix such that [q_ind, u_ind]^T = perm_mat*[q, u]^T
+
+    References
+    ==========
+
+    .. [1] D. L. Peterson, G. Gede, and M. Hubbard, "Symbolic linearization of
+           equations of motion of constrained multibody systems," Multibody
+           Syst Dyn, vol. 33, no. 2, pp. 143-161, Feb. 2015, doi:
+           10.1007/s11044-014-9436-5.
+
+    """
+
+    def __init__(self, f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a, q, u, q_i=None,
+                 q_d=None, u_i=None, u_d=None, r=None, lams=None,
+                 linear_solver='LU'):
+        """
+        Parameters
+        ==========
+
+        f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a : array_like
+            System of equations holding the general system form.
+            Supply empty array or Matrix if the parameter
+            does not exist.
+        q : array_like
+            The generalized coordinates.
+        u : array_like
+            The generalized speeds
+        q_i, u_i : array_like, optional
+            The independent generalized coordinates and speeds.
+        q_d, u_d : array_like, optional
+            The dependent generalized coordinates and speeds.
+        r : array_like, optional
+            The input variables.
+        lams : array_like, optional
+            The lagrange multipliers
+        linear_solver : str, callable
+            Method used to solve the several symbolic linear systems of the
+            form ``A*x=b`` in the linearization process. If a string is
+            supplied, it should be a valid method that can be used with the
+            :meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is
+            supplied, it should have the format ``x = f(A, b)``, where it
+            solves the equations and returns the solution. The default is
+            ``'LU'`` which corresponds to SymPy's ``A.LUsolve(b)``.
+            ``LUsolve()`` is fast to compute but will often result in
+            divide-by-zero and thus ``nan`` results.
+
+        """
+        self.linear_solver = _parse_linear_solver(linear_solver)
+
+        # Generalized equation form
+        self.f_0 = Matrix(f_0)
+        self.f_1 = Matrix(f_1)
+        self.f_2 = Matrix(f_2)
+        self.f_3 = Matrix(f_3)
+        self.f_4 = Matrix(f_4)
+        self.f_c = Matrix(f_c)
+        self.f_v = Matrix(f_v)
+        self.f_a = Matrix(f_a)
+
+        # Generalized equation variables
+        self.q = Matrix(q)
+        self.u = Matrix(u)
+        none_handler = lambda x: Matrix(x) if x else Matrix()
+        self.q_i = none_handler(q_i)
+        self.q_d = none_handler(q_d)
+        self.u_i = none_handler(u_i)
+        self.u_d = none_handler(u_d)
+        self.r = none_handler(r)
+        self.lams = none_handler(lams)
+
+        # Derivatives of generalized equation variables
+        self._qd = self.q.diff(dynamicsymbols._t)
+        self._ud = self.u.diff(dynamicsymbols._t)
+        # If the user doesn't actually use generalized variables, and the
+        # qd and u vectors have any intersecting variables, this can cause
+        # problems. We'll fix this with some hackery, and Dummy variables
+        dup_vars = set(self._qd).intersection(self.u)
+        self._qd_dup = Matrix([var if var not in dup_vars else Dummy() for var
+                               in self._qd])
+
+        # Derive dimesion terms
+        l = len(self.f_c)
+        m = len(self.f_v)
+        n = len(self.q)
+        o = len(self.u)
+        s = len(self.r)
+        k = len(self.lams)
+        dims = namedtuple('dims', ['l', 'm', 'n', 'o', 's', 'k'])
+        self._dims = dims(l, m, n, o, s, k)
+
+        self._Pq = None
+        self._Pqi = None
+        self._Pqd = None
+        self._Pu = None
+        self._Pui = None
+        self._Pud = None
+        self._C_0 = None
+        self._C_1 = None
+        self._C_2 = None
+        self.perm_mat = None
+
+        self._setup_done = False
+
+    def _setup(self):
+        # Calculations here only need to be run once. They are moved out of
+        # the __init__ method to increase the speed of Linearizer creation.
+        self._form_permutation_matrices()
+        self._form_block_matrices()
+        self._form_coefficient_matrices()
+        self._setup_done = True
+
+    def _form_permutation_matrices(self):
+        """Form the permutation matrices Pq and Pu."""
+
+        # Extract dimension variables
+        l, m, n, o, s, k = self._dims
+        # Compute permutation matrices
+        if n != 0:
+            self._Pq = permutation_matrix(self.q, Matrix([self.q_i, self.q_d]))
+            if l > 0:
+                self._Pqi = self._Pq[:, :-l]
+                self._Pqd = self._Pq[:, -l:]
+            else:
+                self._Pqi = self._Pq
+                self._Pqd = Matrix()
+        if o != 0:
+            self._Pu = permutation_matrix(self.u, Matrix([self.u_i, self.u_d]))
+            if m > 0:
+                self._Pui = self._Pu[:, :-m]
+                self._Pud = self._Pu[:, -m:]
+            else:
+                self._Pui = self._Pu
+                self._Pud = Matrix()
+        # Compute combination permutation matrix for computing A and B
+        P_col1 = Matrix([self._Pqi, zeros(o + k, n - l)])
+        P_col2 = Matrix([zeros(n, o - m), self._Pui, zeros(k, o - m)])
+        if P_col1:
+            if P_col2:
+                self.perm_mat = P_col1.row_join(P_col2)
+            else:
+                self.perm_mat = P_col1
+        else:
+            self.perm_mat = P_col2
+
+    def _form_coefficient_matrices(self):
+        """Form the coefficient matrices C_0, C_1, and C_2."""
+
+        # Extract dimension variables
+        l, m, n, o, s, k = self._dims
+        # Build up the coefficient matrices C_0, C_1, and C_2
+        # If there are configuration constraints (l > 0), form C_0 as normal.
+        # If not, C_0 is I_(nxn). Note that this works even if n=0
+        if l > 0:
+            f_c_jac_q = self.f_c.jacobian(self.q)
+            self._C_0 = (eye(n) - self._Pqd *
+                         self.linear_solver(f_c_jac_q*self._Pqd,
+                                            f_c_jac_q))*self._Pqi
+        else:
+            self._C_0 = eye(n)
+        # If there are motion constraints (m > 0), form C_1 and C_2 as normal.
+        # If not, C_1 is 0, and C_2 is I_(oxo). Note that this works even if
+        # o = 0.
+        if m > 0:
+            f_v_jac_u = self.f_v.jacobian(self.u)
+            temp = f_v_jac_u * self._Pud
+            if n != 0:
+                f_v_jac_q = self.f_v.jacobian(self.q)
+                self._C_1 = -self._Pud * self.linear_solver(temp, f_v_jac_q)
+            else:
+                self._C_1 = zeros(o, n)
+            self._C_2 = (eye(o) - self._Pud *
+                         self.linear_solver(temp, f_v_jac_u))*self._Pui
+        else:
+            self._C_1 = zeros(o, n)
+            self._C_2 = eye(o)
+
+    def _form_block_matrices(self):
+        """Form the block matrices for composing M, A, and B."""
+
+        # Extract dimension variables
+        l, m, n, o, s, k = self._dims
+        # Block Matrix Definitions. These are only defined if under certain
+        # conditions. If undefined, an empty matrix is used instead
+        if n != 0:
+            self._M_qq = self.f_0.jacobian(self._qd)
+            self._A_qq = -(self.f_0 + self.f_1).jacobian(self.q)
+        else:
+            self._M_qq = Matrix()
+            self._A_qq = Matrix()
+        if n != 0 and m != 0:
+            self._M_uqc = self.f_a.jacobian(self._qd_dup)
+            self._A_uqc = -self.f_a.jacobian(self.q)
+        else:
+            self._M_uqc = Matrix()
+            self._A_uqc = Matrix()
+        if n != 0 and o - m + k != 0:
+            self._M_uqd = self.f_3.jacobian(self._qd_dup)
+            self._A_uqd = -(self.f_2 + self.f_3 + self.f_4).jacobian(self.q)
+        else:
+            self._M_uqd = Matrix()
+            self._A_uqd = Matrix()
+        if o != 0 and m != 0:
+            self._M_uuc = self.f_a.jacobian(self._ud)
+            self._A_uuc = -self.f_a.jacobian(self.u)
+        else:
+            self._M_uuc = Matrix()
+            self._A_uuc = Matrix()
+        if o != 0 and o - m + k != 0:
+            self._M_uud = self.f_2.jacobian(self._ud)
+            self._A_uud = -(self.f_2 + self.f_3).jacobian(self.u)
+        else:
+            self._M_uud = Matrix()
+            self._A_uud = Matrix()
+        if o != 0 and n != 0:
+            self._A_qu = -self.f_1.jacobian(self.u)
+        else:
+            self._A_qu = Matrix()
+        if k != 0 and o - m + k != 0:
+            self._M_uld = self.f_4.jacobian(self.lams)
+        else:
+            self._M_uld = Matrix()
+        if s != 0 and o - m + k != 0:
+            self._B_u = -self.f_3.jacobian(self.r)
+        else:
+            self._B_u = Matrix()
+
+    def linearize(self, op_point=None, A_and_B=False, simplify=False):
+        """Linearize the system about the operating point. Note that
+        q_op, u_op, qd_op, ud_op must satisfy the equations of motion.
+        These may be either symbolic or numeric.
+
+        Parameters
+        ==========
+        op_point : dict or iterable of dicts, optional
+            Dictionary or iterable of dictionaries containing the operating
+            point conditions for all or a subset of the generalized
+            coordinates, generalized speeds, and time derivatives of the
+            generalized speeds. These will be substituted into the linearized
+            system before the linearization is complete. Leave set to ``None``
+            if you want the operating point to be an arbitrary set of symbols.
+            Note that any reduction in symbols (whether substituted for numbers
+            or expressions with a common parameter) will result in faster
+            runtime.
+        A_and_B : bool, optional
+            If A_and_B=False (default), (M, A, B) is returned and of
+            A_and_B=True, (A, B) is returned. See below.
+        simplify : bool, optional
+            Determines if returned values are simplified before return.
+            For large expressions this may be time consuming. Default is False.
+
+        Returns
+        =======
+        M, A, B : Matrices, ``A_and_B=False``
+            Matrices from the implicit form:
+                ``[M]*[q', u']^T = [A]*[q_ind, u_ind]^T + [B]*r``
+        A, B : Matrices, ``A_and_B=True``
+            Matrices from the explicit form:
+                ``[q_ind', u_ind']^T = [A]*[q_ind, u_ind]^T + [B]*r``
+
+        Notes
+        =====
+
+        Note that the process of solving with A_and_B=True is computationally
+        intensive if there are many symbolic parameters. For this reason, it
+        may be more desirable to use the default A_and_B=False, returning M, A,
+        and B. More values may then be substituted in to these matrices later
+        on. The state space form can then be found as A = P.T*M.LUsolve(A), B =
+        P.T*M.LUsolve(B), where P = Linearizer.perm_mat.
+
+        """
+
+        # Run the setup if needed:
+        if not self._setup_done:
+            self._setup()
+
+        # Compose dict of operating conditions
+        if isinstance(op_point, dict):
+            op_point_dict = op_point
+        elif isinstance(op_point, Iterable):
+            op_point_dict = {}
+            for op in op_point:
+                op_point_dict.update(op)
+        else:
+            op_point_dict = {}
+
+        # Extract dimension variables
+        l, m, n, o, s, k = self._dims
+
+        # Rename terms to shorten expressions
+        M_qq = self._M_qq
+        M_uqc = self._M_uqc
+        M_uqd = self._M_uqd
+        M_uuc = self._M_uuc
+        M_uud = self._M_uud
+        M_uld = self._M_uld
+        A_qq = self._A_qq
+        A_uqc = self._A_uqc
+        A_uqd = self._A_uqd
+        A_qu = self._A_qu
+        A_uuc = self._A_uuc
+        A_uud = self._A_uud
+        B_u = self._B_u
+        C_0 = self._C_0
+        C_1 = self._C_1
+        C_2 = self._C_2
+
+        # Build up Mass Matrix
+        #     |M_qq    0_nxo   0_nxk|
+        # M = |M_uqc   M_uuc   0_mxk|
+        #     |M_uqd   M_uud   M_uld|
+        if o != 0:
+            col2 = Matrix([zeros(n, o), M_uuc, M_uud])
+        if k != 0:
+            col3 = Matrix([zeros(n + m, k), M_uld])
+        if n != 0:
+            col1 = Matrix([M_qq, M_uqc, M_uqd])
+            if o != 0 and k != 0:
+                M = col1.row_join(col2).row_join(col3)
+            elif o != 0:
+                M = col1.row_join(col2)
+            else:
+                M = col1
+        elif k != 0:
+            M = col2.row_join(col3)
+        else:
+            M = col2
+        M_eq = msubs(M, op_point_dict)
+
+        # Build up state coefficient matrix A
+        #     |(A_qq + A_qu*C_1)*C_0       A_qu*C_2|
+        # A = |(A_uqc + A_uuc*C_1)*C_0    A_uuc*C_2|
+        #     |(A_uqd + A_uud*C_1)*C_0    A_uud*C_2|
+        # Col 1 is only defined if n != 0
+        if n != 0:
+            r1c1 = A_qq
+            if o != 0:
+                r1c1 += (A_qu * C_1)
+            r1c1 = r1c1 * C_0
+            if m != 0:
+                r2c1 = A_uqc
+                if o != 0:
+                    r2c1 += (A_uuc * C_1)
+                r2c1 = r2c1 * C_0
+            else:
+                r2c1 = Matrix()
+            if o - m + k != 0:
+                r3c1 = A_uqd
+                if o != 0:
+                    r3c1 += (A_uud * C_1)
+                r3c1 = r3c1 * C_0
+            else:
+                r3c1 = Matrix()
+            col1 = Matrix([r1c1, r2c1, r3c1])
+        else:
+            col1 = Matrix()
+        # Col 2 is only defined if o != 0
+        if o != 0:
+            if n != 0:
+                r1c2 = A_qu * C_2
+            else:
+                r1c2 = Matrix()
+            if m != 0:
+                r2c2 = A_uuc * C_2
+            else:
+                r2c2 = Matrix()
+            if o - m + k != 0:
+                r3c2 = A_uud * C_2
+            else:
+                r3c2 = Matrix()
+            col2 = Matrix([r1c2, r2c2, r3c2])
+        else:
+            col2 = Matrix()
+        if col1:
+            if col2:
+                Amat = col1.row_join(col2)
+            else:
+                Amat = col1
+        else:
+            Amat = col2
+        Amat_eq = msubs(Amat, op_point_dict)
+
+        # Build up the B matrix if there are forcing variables
+        #     |0_(n + m)xs|
+        # B = |B_u        |
+        if s != 0 and o - m + k != 0:
+            Bmat = zeros(n + m, s).col_join(B_u)
+            Bmat_eq = msubs(Bmat, op_point_dict)
+        else:
+            Bmat_eq = Matrix()
+
+        # kwarg A_and_B indicates to return  A, B for forming the equation
+        # dx = [A]x + [B]r, where x = [q_indnd, u_indnd]^T,
+        if A_and_B:
+            A_cont = self.perm_mat.T * self.linear_solver(M_eq, Amat_eq)
+            if Bmat_eq:
+                B_cont = self.perm_mat.T * self.linear_solver(M_eq, Bmat_eq)
+            else:
+                # Bmat = Matrix([]), so no need to sub
+                B_cont = Bmat_eq
+            if simplify:
+                A_cont.simplify()
+                B_cont.simplify()
+            return A_cont, B_cont
+        # Otherwise return M, A, B for forming the equation
+        # [M]dx = [A]x + [B]r, where x = [q, u]^T
+        else:
+            if simplify:
+                M_eq.simplify()
+                Amat_eq.simplify()
+                Bmat_eq.simplify()
+            return M_eq, Amat_eq, Bmat_eq
+
+
+def permutation_matrix(orig_vec, per_vec):
+    """Compute the permutation matrix to change order of
+    orig_vec into order of per_vec.
+
+    Parameters
+    ==========
+
+    orig_vec : array_like
+        Symbols in original ordering.
+    per_vec : array_like
+        Symbols in new ordering.
+
+    Returns
+    =======
+
+    p_matrix : Matrix
+        Permutation matrix such that orig_vec == (p_matrix * per_vec).
+    """
+    if not isinstance(orig_vec, (list, tuple)):
+        orig_vec = flatten(orig_vec)
+    if not isinstance(per_vec, (list, tuple)):
+        per_vec = flatten(per_vec)
+    if set(orig_vec) != set(per_vec):
+        raise ValueError("orig_vec and per_vec must be the same length, "
+                         "and contain the same symbols.")
+    ind_list = [orig_vec.index(i) for i in per_vec]
+    p_matrix = zeros(len(orig_vec))
+    for i, j in enumerate(ind_list):
+        p_matrix[i, j] = 1
+    return p_matrix

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/loads.py

@@ -0,0 +1,177 @@
+from abc import ABC
+from collections import namedtuple
+from sympy.physics.mechanics.body_base import BodyBase
+from sympy.physics.vector import Vector, ReferenceFrame, Point
+
+__all__ = ['LoadBase', 'Force', 'Torque']
+
+
+class LoadBase(ABC, namedtuple('LoadBase', ['location', 'vector'])):
+    """Abstract base class for the various loading types."""
+
+    def __add__(self, other):
+        raise TypeError(f"unsupported operand type(s) for +: "
+                        f"'{self.__class__.__name__}' and "
+                        f"'{other.__class__.__name__}'")
+
+    def __mul__(self, other):
+        raise TypeError(f"unsupported operand type(s) for *: "
+                        f"'{self.__class__.__name__}' and "
+                        f"'{other.__class__.__name__}'")
+
+    __radd__ = __add__
+    __rmul__ = __mul__
+
+
+class Force(LoadBase):
+    """Force acting upon a point.
+
+    Explanation
+    ===========
+
+    A force is a vector that is bound to a line of action. This class stores
+    both a point, which lies on the line of action, and the vector. A tuple can
+    also be used, with the location as the first entry and the vector as second
+    entry.
+
+    Examples
+    ========
+
+    A force of magnitude 2 along N.x acting on a point Po can be created as
+    follows:
+
+    >>> from sympy.physics.mechanics import Point, ReferenceFrame, Force
+    >>> N = ReferenceFrame('N')
+    >>> Po = Point('Po')
+    >>> Force(Po, 2 * N.x)
+    (Po, 2*N.x)
+
+    If a body is supplied, then the center of mass of that body is used.
+
+    >>> from sympy.physics.mechanics import Particle
+    >>> P = Particle('P', point=Po)
+    >>> Force(P, 2 * N.x)
+    (Po, 2*N.x)
+
+    """
+
+    def __new__(cls, point, force):
+        if isinstance(point, BodyBase):
+            point = point.masscenter
+        if not isinstance(point, Point):
+            raise TypeError('Force location should be a Point.')
+        if not isinstance(force, Vector):
+            raise TypeError('Force vector should be a Vector.')
+        return super().__new__(cls, point, force)
+
+    def __repr__(self):
+        return (f'{self.__class__.__name__}(point={self.point}, '
+                f'force={self.force})')
+
+    @property
+    def point(self):
+        return self.location
+
+    @property
+    def force(self):
+        return self.vector
+
+
+class Torque(LoadBase):
+    """Torque acting upon a frame.
+
+    Explanation
+    ===========
+
+    A torque is a free vector that is acting on a reference frame, which is
+    associated with a rigid body. This class stores both the frame and the
+    vector. A tuple can also be used, with the location as the first item and
+    the vector as second item.
+
+    Examples
+    ========
+
+    A torque of magnitude 2 about N.x acting on a frame N can be created as
+    follows:
+
+    >>> from sympy.physics.mechanics import ReferenceFrame, Torque
+    >>> N = ReferenceFrame('N')
+    >>> Torque(N, 2 * N.x)
+    (N, 2*N.x)
+
+    If a body is supplied, then the frame fixed to that body is used.
+
+    >>> from sympy.physics.mechanics import RigidBody
+    >>> rb = RigidBody('rb', frame=N)
+    >>> Torque(rb, 2 * N.x)
+    (N, 2*N.x)
+
+    """
+
+    def __new__(cls, frame, torque):
+        if isinstance(frame, BodyBase):
+            frame = frame.frame
+        if not isinstance(frame, ReferenceFrame):
+            raise TypeError('Torque location should be a ReferenceFrame.')
+        if not isinstance(torque, Vector):
+            raise TypeError('Torque vector should be a Vector.')
+        return super().__new__(cls, frame, torque)
+
+    def __repr__(self):
+        return (f'{self.__class__.__name__}(frame={self.frame}, '
+                f'torque={self.torque})')
+
+    @property
+    def frame(self):
+        return self.location
+
+    @property
+    def torque(self):
+        return self.vector
+
+
+def gravity(acceleration, *bodies):
+    """
+    Returns a list of gravity forces given the acceleration
+    due to gravity and any number of particles or rigidbodies.
+
+    Example
+    =======
+
+    >>> from sympy.physics.mechanics import ReferenceFrame, Particle, RigidBody
+    >>> from sympy.physics.mechanics.loads import gravity
+    >>> from sympy import symbols
+    >>> N = ReferenceFrame('N')
+    >>> g = symbols('g')
+    >>> P = Particle('P')
+    >>> B = RigidBody('B')
+    >>> gravity(g*N.y, P, B)
+    [(P_masscenter, P_mass*g*N.y),
+     (B_masscenter, B_mass*g*N.y)]
+
+    """
+
+    gravity_force = []
+    for body in bodies:
+        if not isinstance(body, BodyBase):
+            raise TypeError(f'{type(body)} is not a body type')
+        gravity_force.append(Force(body.masscenter, body.mass * acceleration))
+    return gravity_force
+
+
+def _parse_load(load):
+    """Helper function to parse loads and convert tuples to load objects."""
+    if isinstance(load, LoadBase):
+        return load
+    elif isinstance(load, tuple):
+        if len(load) != 2:
+            raise ValueError(f'Load {load} should have a length of 2.')
+        if isinstance(load[0], Point):
+            return Force(load[0], load[1])
+        elif isinstance(load[0], ReferenceFrame):
+            return Torque(load[0], load[1])
+        else:
+            raise ValueError(f'Load not recognized. The load location {load[0]}'
+                             f' should either be a Point or a ReferenceFrame.')
+    raise TypeError(f'Load type {type(load)} not recognized as a load. It '
+                    f'should be a Force, Torque or tuple.')

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/method.py

@@ -0,0 +1,39 @@
+from abc import ABC, abstractmethod
+
+class _Methods(ABC):
+    """Abstract Base Class for all methods."""
+
+    @abstractmethod
+    def q(self):
+        pass
+
+    @abstractmethod
+    def u(self):
+        pass
+
+    @abstractmethod
+    def bodies(self):
+        pass
+
+    @abstractmethod
+    def loads(self):
+        pass
+
+    @abstractmethod
+    def mass_matrix(self):
+        pass
+
+    @abstractmethod
+    def forcing(self):
+        pass
+
+    @abstractmethod
+    def mass_matrix_full(self):
+        pass
+
+    @abstractmethod
+    def forcing_full(self):
+        pass
+
+    def _form_eoms(self):
+        raise NotImplementedError("Subclasses must implement this.")

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/models.py

@@ -0,0 +1,230 @@
+#!/usr/bin/env python
+"""This module contains some sample symbolic models used for testing and
+examples."""
+
+# Internal imports
+from sympy.core import backend as sm
+import sympy.physics.mechanics as me
+
+
+def multi_mass_spring_damper(n=1, apply_gravity=False,
+                             apply_external_forces=False):
+    r"""Returns a system containing the symbolic equations of motion and
+    associated variables for a simple multi-degree of freedom point mass,
+    spring, damper system with optional gravitational and external
+    specified forces. For example, a two mass system under the influence of
+    gravity and external forces looks like:
+
+    ::
+
+        ----------------
+         |     |     |   | g
+         \    | |    |   V
+      k0 /    --- c0 |
+         |     |     | x0, v0
+        ---------    V
+        |  m0   | -----
+        ---------    |
+         | |   |     |
+         \ v  | |    |
+      k1 / f0 --- c1 |
+         |     |     | x1, v1
+        ---------    V
+        |  m1   | -----
+        ---------
+           | f1
+           V
+
+    Parameters
+    ==========
+
+    n : integer
+        The number of masses in the serial chain.
+    apply_gravity : boolean
+        If true, gravity will be applied to each mass.
+    apply_external_forces : boolean
+        If true, a time varying external force will be applied to each mass.
+
+    Returns
+    =======
+
+    kane : sympy.physics.mechanics.kane.KanesMethod
+        A KanesMethod object.
+
+    """
+
+    mass = sm.symbols('m:{}'.format(n))
+    stiffness = sm.symbols('k:{}'.format(n))
+    damping = sm.symbols('c:{}'.format(n))
+
+    acceleration_due_to_gravity = sm.symbols('g')
+
+    coordinates = me.dynamicsymbols('x:{}'.format(n))
+    speeds = me.dynamicsymbols('v:{}'.format(n))
+    specifieds = me.dynamicsymbols('f:{}'.format(n))
+
+    ceiling = me.ReferenceFrame('N')
+    origin = me.Point('origin')
+    origin.set_vel(ceiling, 0)
+
+    points = [origin]
+    kinematic_equations = []
+    particles = []
+    forces = []
+
+    for i in range(n):
+
+        center = points[-1].locatenew('center{}'.format(i),
+                                      coordinates[i] * ceiling.x)
+        center.set_vel(ceiling, points[-1].vel(ceiling) +
+                       speeds[i] * ceiling.x)
+        points.append(center)
+
+        block = me.Particle('block{}'.format(i), center, mass[i])
+
+        kinematic_equations.append(speeds[i] - coordinates[i].diff())
+
+        total_force = (-stiffness[i] * coordinates[i] -
+                       damping[i] * speeds[i])
+        try:
+            total_force += (stiffness[i + 1] * coordinates[i + 1] +
+                            damping[i + 1] * speeds[i + 1])
+        except IndexError:  # no force from below on last mass
+            pass
+
+        if apply_gravity:
+            total_force += mass[i] * acceleration_due_to_gravity
+
+        if apply_external_forces:
+            total_force += specifieds[i]
+
+        forces.append((center, total_force * ceiling.x))
+
+        particles.append(block)
+
+    kane = me.KanesMethod(ceiling, q_ind=coordinates, u_ind=speeds,
+                          kd_eqs=kinematic_equations)
+    kane.kanes_equations(particles, forces)
+
+    return kane
+
+
+def n_link_pendulum_on_cart(n=1, cart_force=True, joint_torques=False):
+    r"""Returns the system containing the symbolic first order equations of
+    motion for a 2D n-link pendulum on a sliding cart under the influence of
+    gravity.
+
+    ::
+
+                  |
+         o    y   v
+          \ 0 ^   g
+           \  |
+          --\-|----
+          |  \|   |
+      F-> |   o --|---> x
+          |       |
+          ---------
+           o     o
+
+    Parameters
+    ==========
+
+    n : integer
+        The number of links in the pendulum.
+    cart_force : boolean, default=True
+        If true an external specified lateral force is applied to the cart.
+    joint_torques : boolean, default=False
+        If true joint torques will be added as specified inputs at each
+        joint.
+
+    Returns
+    =======
+
+    kane : sympy.physics.mechanics.kane.KanesMethod
+        A KanesMethod object.
+
+    Notes
+    =====
+
+    The degrees of freedom of the system are n + 1, i.e. one for each
+    pendulum link and one for the lateral motion of the cart.
+
+    M x' = F, where x = [u0, ..., un+1, q0, ..., qn+1]
+
+    The joint angles are all defined relative to the ground where the x axis
+    defines the ground line and the y axis points up. The joint torques are
+    applied between each adjacent link and the between the cart and the
+    lower link where a positive torque corresponds to positive angle.
+
+    """
+    if n <= 0:
+        raise ValueError('The number of links must be a positive integer.')
+
+    q = me.dynamicsymbols('q:{}'.format(n + 1))
+    u = me.dynamicsymbols('u:{}'.format(n + 1))
+
+    if joint_torques is True:
+        T = me.dynamicsymbols('T1:{}'.format(n + 1))
+
+    m = sm.symbols('m:{}'.format(n + 1))
+    l = sm.symbols('l:{}'.format(n))
+    g, t = sm.symbols('g t')
+
+    I = me.ReferenceFrame('I')
+    O = me.Point('O')
+    O.set_vel(I, 0)
+
+    P0 = me.Point('P0')
+    P0.set_pos(O, q[0] * I.x)
+    P0.set_vel(I, u[0] * I.x)
+    Pa0 = me.Particle('Pa0', P0, m[0])
+
+    frames = [I]
+    points = [P0]
+    particles = [Pa0]
+    forces = [(P0, -m[0] * g * I.y)]
+    kindiffs = [q[0].diff(t) - u[0]]
+
+    if cart_force is True or joint_torques is True:
+        specified = []
+    else:
+        specified = None
+
+    for i in range(n):
+        Bi = I.orientnew('B{}'.format(i), 'Axis', [q[i + 1], I.z])
+        Bi.set_ang_vel(I, u[i + 1] * I.z)
+        frames.append(Bi)
+
+        Pi = points[-1].locatenew('P{}'.format(i + 1), l[i] * Bi.y)
+        Pi.v2pt_theory(points[-1], I, Bi)
+        points.append(Pi)
+
+        Pai = me.Particle('Pa' + str(i + 1), Pi, m[i + 1])
+        particles.append(Pai)
+
+        forces.append((Pi, -m[i + 1] * g * I.y))
+
+        if joint_torques is True:
+
+            specified.append(T[i])
+
+            if i == 0:
+                forces.append((I, -T[i] * I.z))
+
+            if i == n - 1:
+                forces.append((Bi, T[i] * I.z))
+            else:
+                forces.append((Bi, T[i] * I.z - T[i + 1] * I.z))
+
+        kindiffs.append(q[i + 1].diff(t) - u[i + 1])
+
+    if cart_force is True:
+        F = me.dynamicsymbols('F')
+        forces.append((P0, F * I.x))
+        specified.append(F)
+
+    kane = me.KanesMethod(I, q_ind=q, u_ind=u, kd_eqs=kindiffs)
+    kane.kanes_equations(particles, forces)
+
+    return kane

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/particle.py

@@ -0,0 +1,209 @@
+from sympy import S
+from sympy.physics.vector import cross, dot
+from sympy.physics.mechanics.body_base import BodyBase
+from sympy.physics.mechanics.inertia import inertia_of_point_mass
+from sympy.utilities.exceptions import sympy_deprecation_warning
+
+__all__ = ['Particle']
+
+
+class Particle(BodyBase):
+    """A particle.
+
+    Explanation
+    ===========
+
+    Particles have a non-zero mass and lack spatial extension; they take up no
+    space.
+
+    Values need to be supplied on initialization, but can be changed later.
+
+    Parameters
+    ==========
+
+    name : str
+        Name of particle
+    point : Point
+        A physics/mechanics Point which represents the position, velocity, and
+        acceleration of this Particle
+    mass : Sympifyable
+        A SymPy expression representing the Particle's mass
+    potential_energy : Sympifyable
+        The potential energy of the Particle.
+
+    Examples
+    ========
+
+    >>> from sympy.physics.mechanics import Particle, Point
+    >>> from sympy import Symbol
+    >>> po = Point('po')
+    >>> m = Symbol('m')
+    >>> pa = Particle('pa', po, m)
+    >>> # Or you could change these later
+    >>> pa.mass = m
+    >>> pa.point = po
+
+    """
+    point = BodyBase.masscenter
+
+    def __init__(self, name, point=None, mass=None):
+        super().__init__(name, point, mass)
+
+    def linear_momentum(self, frame):
+        """Linear momentum of the particle.
+
+        Explanation
+        ===========
+
+        The linear momentum L, of a particle P, with respect to frame N is
+        given by:
+
+        L = m * v
+
+        where m is the mass of the particle, and v is the velocity of the
+        particle in the frame N.
+
+        Parameters
+        ==========
+
+        frame : ReferenceFrame
+            The frame in which linear momentum is desired.
+
+        Examples
+        ========
+
+        >>> from sympy.physics.mechanics import Particle, Point, ReferenceFrame
+        >>> from sympy.physics.mechanics import dynamicsymbols
+        >>> from sympy.physics.vector import init_vprinting
+        >>> init_vprinting(pretty_print=False)
+        >>> m, v = dynamicsymbols('m v')
+        >>> N = ReferenceFrame('N')
+        >>> P = Point('P')
+        >>> A = Particle('A', P, m)
+        >>> P.set_vel(N, v * N.x)
+        >>> A.linear_momentum(N)
+        m*v*N.x
+
+        """
+
+        return self.mass * self.point.vel(frame)
+
+    def angular_momentum(self, point, frame):
+        """Angular momentum of the particle about the point.
+
+        Explanation
+        ===========
+
+        The angular momentum H, about some point O of a particle, P, is given
+        by:
+
+        ``H = cross(r, m * v)``
+
+        where r is the position vector from point O to the particle P, m is
+        the mass of the particle, and v is the velocity of the particle in
+        the inertial frame, N.
+
+        Parameters
+        ==========
+
+        point : Point
+            The point about which angular momentum of the particle is desired.
+
+        frame : ReferenceFrame
+            The frame in which angular momentum is desired.
+
+        Examples
+        ========
+
+        >>> from sympy.physics.mechanics import Particle, Point, ReferenceFrame
+        >>> from sympy.physics.mechanics import dynamicsymbols
+        >>> from sympy.physics.vector import init_vprinting
+        >>> init_vprinting(pretty_print=False)
+        >>> m, v, r = dynamicsymbols('m v r')
+        >>> N = ReferenceFrame('N')
+        >>> O = Point('O')
+        >>> A = O.locatenew('A', r * N.x)
+        >>> P = Particle('P', A, m)
+        >>> P.point.set_vel(N, v * N.y)
+        >>> P.angular_momentum(O, N)
+        m*r*v*N.z
+
+        """
+
+        return cross(self.point.pos_from(point),
+                     self.mass * self.point.vel(frame))
+
+    def kinetic_energy(self, frame):
+        """Kinetic energy of the particle.
+
+        Explanation
+        ===========
+
+        The kinetic energy, T, of a particle, P, is given by:
+
+        ``T = 1/2 (dot(m * v, v))``
+
+        where m is the mass of particle P, and v is the velocity of the
+        particle in the supplied ReferenceFrame.
+
+        Parameters
+        ==========
+
+        frame : ReferenceFrame
+            The Particle's velocity is typically defined with respect to
+            an inertial frame but any relevant frame in which the velocity is
+            known can be supplied.
+
+        Examples
+        ========
+
+        >>> from sympy.physics.mechanics import Particle, Point, ReferenceFrame
+        >>> from sympy import symbols
+        >>> m, v, r = symbols('m v r')
+        >>> N = ReferenceFrame('N')
+        >>> O = Point('O')
+        >>> P = Particle('P', O, m)
+        >>> P.point.set_vel(N, v * N.y)
+        >>> P.kinetic_energy(N)
+        m*v**2/2
+
+        """
+
+        return S.Half * self.mass * dot(self.point.vel(frame),
+                                        self.point.vel(frame))
+
+    def set_potential_energy(self, scalar):
+        sympy_deprecation_warning(
+            """
+The sympy.physics.mechanics.Particle.set_potential_energy()
+method is deprecated. Instead use
+
+    P.potential_energy = scalar
+            """,
+        deprecated_since_version="1.5",
+        active_deprecations_target="deprecated-set-potential-energy",
+        )
+        self.potential_energy = scalar
+
+    def parallel_axis(self, point, frame):
+        """Returns an inertia dyadic of the particle with respect to another
+        point and frame.
+
+        Parameters
+        ==========
+
+        point : sympy.physics.vector.Point
+            The point to express the inertia dyadic about.
+        frame : sympy.physics.vector.ReferenceFrame
+            The reference frame used to construct the dyadic.
+
+        Returns
+        =======
+
+        inertia : sympy.physics.vector.Dyadic
+            The inertia dyadic of the particle expressed about the provided
+            point and frame.
+
+        """
+        return inertia_of_point_mass(self.mass, self.point.pos_from(point),
+                                     frame)

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/pathway.py

@@ -0,0 +1,688 @@
+"""Implementations of pathways for use by actuators."""
+
+from abc import ABC, abstractmethod
+
+from sympy.core.singleton import S
+from sympy.physics.mechanics.loads import Force
+from sympy.physics.mechanics.wrapping_geometry import WrappingGeometryBase
+from sympy.physics.vector import Point, dynamicsymbols
+
+
+__all__ = ['PathwayBase', 'LinearPathway', 'ObstacleSetPathway',
+           'WrappingPathway']
+
+
+class PathwayBase(ABC):
+    """Abstract base class for all pathway classes to inherit from.
+
+    Notes
+    =====
+
+    Instances of this class cannot be directly instantiated by users. However,
+    it can be used to created custom pathway types through subclassing.
+
+    """
+
+    def __init__(self, *attachments):
+        """Initializer for ``PathwayBase``."""
+        self.attachments = attachments
+
+    @property
+    def attachments(self):
+        """The pair of points defining a pathway's ends."""
+        return self._attachments
+
+    @attachments.setter
+    def attachments(self, attachments):
+        if hasattr(self, '_attachments'):
+            msg = (
+                f'Can\'t set attribute `attachments` to {repr(attachments)} '
+                f'as it is immutable.'
+            )
+            raise AttributeError(msg)
+        if len(attachments) != 2:
+            msg = (
+                f'Value {repr(attachments)} passed to `attachments` was an '
+                f'iterable of length {len(attachments)}, must be an iterable '
+                f'of length 2.'
+            )
+            raise ValueError(msg)
+        for i, point in enumerate(attachments):
+            if not isinstance(point, Point):
+                msg = (
+                    f'Value {repr(point)} passed to `attachments` at index '
+                    f'{i} was of type {type(point)}, must be {Point}.'
+                )
+                raise TypeError(msg)
+        self._attachments = tuple(attachments)
+
+    @property
+    @abstractmethod
+    def length(self):
+        """An expression representing the pathway's length."""
+        pass
+
+    @property
+    @abstractmethod
+    def extension_velocity(self):
+        """An expression representing the pathway's extension velocity."""
+        pass
+
+    @abstractmethod
+    def to_loads(self, force):
+        """Loads required by the equations of motion method classes.
+
+        Explanation
+        ===========
+
+        ``KanesMethod`` requires a list of ``Point``-``Vector`` tuples to be
+        passed to the ``loads`` parameters of its ``kanes_equations`` method
+        when constructing the equations of motion. This method acts as a
+        utility to produce the correctly-structred pairs of points and vectors
+        required so that these can be easily concatenated with other items in
+        the list of loads and passed to ``KanesMethod.kanes_equations``. These
+        loads are also in the correct form to also be passed to the other
+        equations of motion method classes, e.g. ``LagrangesMethod``.
+
+        """
+        pass
+
+    def __repr__(self):
+        """Default representation of a pathway."""
+        attachments = ', '.join(str(a) for a in self.attachments)
+        return f'{self.__class__.__name__}({attachments})'
+
+
+class LinearPathway(PathwayBase):
+    """Linear pathway between a pair of attachment points.
+
+    Explanation
+    ===========
+
+    A linear pathway forms a straight-line segment between two points and is
+    the simplest pathway that can be formed. It will not interact with any
+    other objects in the system, i.e. a ``LinearPathway`` will intersect other
+    objects to ensure that the path between its two ends (its attachments) is
+    the shortest possible.
+
+    A linear pathway is made up of two points that can move relative to each
+    other, and a pair of equal and opposite forces acting on the points. If the
+    positive time-varying Euclidean distance between the two points is defined,
+    then the "extension velocity" is the time derivative of this distance. The
+    extension velocity is positive when the two points are moving away from
+    each other and negative when moving closer to each other. The direction for
+    the force acting on either point is determined by constructing a unit
+    vector directed from the other point to this point. This establishes a sign
+    convention such that a positive force magnitude tends to push the points
+    apart. The following diagram shows the positive force sense and the
+    distance between the points::
+
+       P           Q
+       o<--- F --->o
+       |           |
+       |<--l(t)--->|
+
+    Examples
+    ========
+
+    >>> from sympy.physics.mechanics import LinearPathway
+
+    To construct a pathway, two points are required to be passed to the
+    ``attachments`` parameter as a ``tuple``.
+
+    >>> from sympy.physics.mechanics import Point
+    >>> pA, pB = Point('pA'), Point('pB')
+    >>> linear_pathway = LinearPathway(pA, pB)
+    >>> linear_pathway
+    LinearPathway(pA, pB)
+
+    The pathway created above isn't very interesting without the positions and
+    velocities of its attachment points being described. Without this its not
+    possible to describe how the pathway moves, i.e. its length or its
+    extension velocity.
+
+    >>> from sympy.physics.mechanics import ReferenceFrame
+    >>> from sympy.physics.vector import dynamicsymbols
+    >>> N = ReferenceFrame('N')
+    >>> q = dynamicsymbols('q')
+    >>> pB.set_pos(pA, q*N.x)
+    >>> pB.pos_from(pA)
+    q(t)*N.x
+
+    A pathway's length can be accessed via its ``length`` attribute.
+
+    >>> linear_pathway.length
+    sqrt(q(t)**2)
+
+    Note how what appears to be an overly-complex expression is returned. This
+    is actually required as it ensures that a pathway's length is always
+    positive.
+
+    A pathway's extension velocity can be accessed similarly via its
+    ``extension_velocity`` attribute.
+
+    >>> linear_pathway.extension_velocity
+    sqrt(q(t)**2)*Derivative(q(t), t)/q(t)
+
+    Parameters
+    ==========
+
+    attachments : tuple[Point, Point]
+        Pair of ``Point`` objects between which the linear pathway spans.
+        Constructor expects two points to be passed, e.g.
+        ``LinearPathway(Point('pA'), Point('pB'))``. More or fewer points will
+        cause an error to be thrown.
+
+    """
+
+    def __init__(self, *attachments):
+        """Initializer for ``LinearPathway``.
+
+        Parameters
+        ==========
+
+        attachments : Point
+            Pair of ``Point`` objects between which the linear pathway spans.
+            Constructor expects two points to be passed, e.g.
+            ``LinearPathway(Point('pA'), Point('pB'))``. More or fewer points
+            will cause an error to be thrown.
+
+        """
+        super().__init__(*attachments)
+
+    @property
+    def length(self):
+        """Exact analytical expression for the pathway's length."""
+        return _point_pair_length(*self.attachments)
+
+    @property
+    def extension_velocity(self):
+        """Exact analytical expression for the pathway's extension velocity."""
+        return _point_pair_extension_velocity(*self.attachments)
+
+    def to_loads(self, force):
+        """Loads required by the equations of motion method classes.
+
+        Explanation
+        ===========
+
+        ``KanesMethod`` requires a list of ``Point``-``Vector`` tuples to be
+        passed to the ``loads`` parameters of its ``kanes_equations`` method
+        when constructing the equations of motion. This method acts as a
+        utility to produce the correctly-structred pairs of points and vectors
+        required so that these can be easily concatenated with other items in
+        the list of loads and passed to ``KanesMethod.kanes_equations``. These
+        loads are also in the correct form to also be passed to the other
+        equations of motion method classes, e.g. ``LagrangesMethod``.
+
+        Examples
+        ========
+
+        The below example shows how to generate the loads produced in a linear
+        actuator that produces an expansile force ``F``. First, create a linear
+        actuator between two points separated by the coordinate ``q`` in the
+        ``x`` direction of the global frame ``N``.
+
+        >>> from sympy.physics.mechanics import (LinearPathway, Point,
+        ...     ReferenceFrame)
+        >>> from sympy.physics.vector import dynamicsymbols
+        >>> q = dynamicsymbols('q')
+        >>> N = ReferenceFrame('N')
+        >>> pA, pB = Point('pA'), Point('pB')
+        >>> pB.set_pos(pA, q*N.x)
+        >>> linear_pathway = LinearPathway(pA, pB)
+
+        Now create a symbol ``F`` to describe the magnitude of the (expansile)
+        force that will be produced along the pathway. The list of loads that
+        ``KanesMethod`` requires can be produced by calling the pathway's
+        ``to_loads`` method with ``F`` passed as the only argument.
+
+        >>> from sympy import symbols
+        >>> F = symbols('F')
+        >>> linear_pathway.to_loads(F)
+        [(pA, - F*q(t)/sqrt(q(t)**2)*N.x), (pB, F*q(t)/sqrt(q(t)**2)*N.x)]
+
+        Parameters
+        ==========
+
+        force : Expr
+            Magnitude of the force acting along the length of the pathway. As
+            per the sign conventions for the pathway length, pathway extension
+            velocity, and pair of point forces, if this ``Expr`` is positive
+            then the force will act to push the pair of points away from one
+            another (it is expansile).
+
+        """
+        relative_position = _point_pair_relative_position(*self.attachments)
+        loads = [
+            Force(self.attachments[0], -force*relative_position/self.length),
+            Force(self.attachments[-1], force*relative_position/self.length),
+        ]
+        return loads
+
+
+class ObstacleSetPathway(PathwayBase):
+    """Obstacle-set pathway between a set of attachment points.
+
+    Explanation
+    ===========
+
+    An obstacle-set pathway forms a series of straight-line segment between
+    pairs of consecutive points in a set of points. It is similiar to multiple
+    linear pathways joined end-to-end. It will not interact with any other
+    objects in the system, i.e. an ``ObstacleSetPathway`` will intersect other
+    objects to ensure that the path between its pairs of points (its
+    attachments) is the shortest possible.
+
+    Examples
+    ========
+
+    To construct an obstacle-set pathway, three or more points are required to
+    be passed to the ``attachments`` parameter as a ``tuple``.
+
+    >>> from sympy.physics.mechanics import ObstacleSetPathway, Point
+    >>> pA, pB, pC, pD = Point('pA'), Point('pB'), Point('pC'), Point('pD')
+    >>> obstacle_set_pathway = ObstacleSetPathway(pA, pB, pC, pD)
+    >>> obstacle_set_pathway
+    ObstacleSetPathway(pA, pB, pC, pD)
+
+    The pathway created above isn't very interesting without the positions and
+    velocities of its attachment points being described. Without this its not
+    possible to describe how the pathway moves, i.e. its length or its
+    extension velocity.
+
+    >>> from sympy import cos, sin
+    >>> from sympy.physics.mechanics import ReferenceFrame
+    >>> from sympy.physics.vector import dynamicsymbols
+    >>> N = ReferenceFrame('N')
+    >>> q = dynamicsymbols('q')
+    >>> pO = Point('pO')
+    >>> pA.set_pos(pO, N.y)
+    >>> pB.set_pos(pO, -N.x)
+    >>> pC.set_pos(pA, cos(q) * N.x - (sin(q) + 1) * N.y)
+    >>> pD.set_pos(pA, sin(q) * N.x + (cos(q) - 1) * N.y)
+    >>> pB.pos_from(pA)
+    - N.x - N.y
+    >>> pC.pos_from(pA)
+    cos(q(t))*N.x + (-sin(q(t)) - 1)*N.y
+    >>> pD.pos_from(pA)
+    sin(q(t))*N.x + (cos(q(t)) - 1)*N.y
+
+    A pathway's length can be accessed via its ``length`` attribute.
+
+    >>> obstacle_set_pathway.length.simplify()
+    sqrt(2)*(sqrt(cos(q(t)) + 1) + 2)
+
+    A pathway's extension velocity can be accessed similarly via its
+    ``extension_velocity`` attribute.
+
+    >>> obstacle_set_pathway.extension_velocity.simplify()
+    -sqrt(2)*sin(q(t))*Derivative(q(t), t)/(2*sqrt(cos(q(t)) + 1))
+
+    Parameters
+    ==========
+
+    attachments : tuple[Point, Point]
+        The set of ``Point`` objects that define the segmented obstacle-set
+        pathway.
+
+    """
+
+    def __init__(self, *attachments):
+        """Initializer for ``ObstacleSetPathway``.
+
+        Parameters
+        ==========
+
+        attachments : tuple[Point, ...]
+            The set of ``Point`` objects that define the segmented obstacle-set
+            pathway.
+
+        """
+        super().__init__(*attachments)
+
+    @property
+    def attachments(self):
+        """The set of points defining a pathway's segmented path."""
+        return self._attachments
+
+    @attachments.setter
+    def attachments(self, attachments):
+        if hasattr(self, '_attachments'):
+            msg = (
+                f'Can\'t set attribute `attachments` to {repr(attachments)} '
+                f'as it is immutable.'
+            )
+            raise AttributeError(msg)
+        if len(attachments) <= 2:
+            msg = (
+                f'Value {repr(attachments)} passed to `attachments` was an '
+                f'iterable of length {len(attachments)}, must be an iterable '
+                f'of length 3 or greater.'
+            )
+            raise ValueError(msg)
+        for i, point in enumerate(attachments):
+            if not isinstance(point, Point):
+                msg = (
+                    f'Value {repr(point)} passed to `attachments` at index '
+                    f'{i} was of type {type(point)}, must be {Point}.'
+                )
+                raise TypeError(msg)
+        self._attachments = tuple(attachments)
+
+    @property
+    def length(self):
+        """Exact analytical expression for the pathway's length."""
+        length = S.Zero
+        attachment_pairs = zip(self.attachments[:-1], self.attachments[1:])
+        for attachment_pair in attachment_pairs:
+            length += _point_pair_length(*attachment_pair)
+        return length
+
+    @property
+    def extension_velocity(self):
+        """Exact analytical expression for the pathway's extension velocity."""
+        extension_velocity = S.Zero
+        attachment_pairs = zip(self.attachments[:-1], self.attachments[1:])
+        for attachment_pair in attachment_pairs:
+            extension_velocity += _point_pair_extension_velocity(*attachment_pair)
+        return extension_velocity
+
+    def to_loads(self, force):
+        """Loads required by the equations of motion method classes.
+
+        Explanation
+        ===========
+
+        ``KanesMethod`` requires a list of ``Point``-``Vector`` tuples to be
+        passed to the ``loads`` parameters of its ``kanes_equations`` method
+        when constructing the equations of motion. This method acts as a
+        utility to produce the correctly-structred pairs of points and vectors
+        required so that these can be easily concatenated with other items in
+        the list of loads and passed to ``KanesMethod.kanes_equations``. These
+        loads are also in the correct form to also be passed to the other
+        equations of motion method classes, e.g. ``LagrangesMethod``.
+
+        Examples
+        ========
+
+        The below example shows how to generate the loads produced in an
+        actuator that follows an obstacle-set pathway between four points and
+        produces an expansile force ``F``. First, create a pair of reference
+        frames, ``A`` and ``B``, in which the four points ``pA``, ``pB``,
+        ``pC``, and ``pD`` will be located. The first two points in frame ``A``
+        and the second two in frame ``B``. Frame ``B`` will also be oriented
+        such that it relates to ``A`` via a rotation of ``q`` about an axis
+        ``N.z`` in a global frame (``N.z``, ``A.z``, and ``B.z`` are parallel).
+
+        >>> from sympy.physics.mechanics import (ObstacleSetPathway, Point,
+        ...     ReferenceFrame)
+        >>> from sympy.physics.vector import dynamicsymbols
+        >>> q = dynamicsymbols('q')
+        >>> N = ReferenceFrame('N')
+        >>> N = ReferenceFrame('N')
+        >>> A = N.orientnew('A', 'axis', (0, N.x))
+        >>> B = A.orientnew('B', 'axis', (q, N.z))
+        >>> pO = Point('pO')
+        >>> pA, pB, pC, pD = Point('pA'), Point('pB'), Point('pC'), Point('pD')
+        >>> pA.set_pos(pO, A.x)
+        >>> pB.set_pos(pO, -A.y)
+        >>> pC.set_pos(pO, B.y)
+        >>> pD.set_pos(pO, B.x)
+        >>> obstacle_set_pathway = ObstacleSetPathway(pA, pB, pC, pD)
+
+        Now create a symbol ``F`` to describe the magnitude of the (expansile)
+        force that will be produced along the pathway. The list of loads that
+        ``KanesMethod`` requires can be produced by calling the pathway's
+        ``to_loads`` method with ``F`` passed as the only argument.
+
+        >>> from sympy import Symbol
+        >>> F = Symbol('F')
+        >>> obstacle_set_pathway.to_loads(F)
+        [(pA, sqrt(2)*F/2*A.x + sqrt(2)*F/2*A.y),
+         (pB, - sqrt(2)*F/2*A.x - sqrt(2)*F/2*A.y),
+         (pB, - F/sqrt(2*cos(q(t)) + 2)*A.y - F/sqrt(2*cos(q(t)) + 2)*B.y),
+         (pC, F/sqrt(2*cos(q(t)) + 2)*A.y + F/sqrt(2*cos(q(t)) + 2)*B.y),
+         (pC, - sqrt(2)*F/2*B.x + sqrt(2)*F/2*B.y),
+         (pD, sqrt(2)*F/2*B.x - sqrt(2)*F/2*B.y)]
+
+        Parameters
+        ==========
+
+        force : Expr
+            The force acting along the length of the pathway. It is assumed
+            that this ``Expr`` represents an expansile force.
+
+        """
+        loads = []
+        attachment_pairs = zip(self.attachments[:-1], self.attachments[1:])
+        for attachment_pair in attachment_pairs:
+            relative_position = _point_pair_relative_position(*attachment_pair)
+            length = _point_pair_length(*attachment_pair)
+            loads.extend([
+                Force(attachment_pair[0], -force*relative_position/length),
+                Force(attachment_pair[1], force*relative_position/length),
+            ])
+        return loads
+
+
+class WrappingPathway(PathwayBase):
+    """Pathway that wraps a geometry object.
+
+    Explanation
+    ===========
+
+    A wrapping pathway interacts with a geometry object and forms a path that
+    wraps smoothly along its surface. The wrapping pathway along the geometry
+    object will be the geodesic that the geometry object defines based on the
+    two points. It will not interact with any other objects in the system, i.e.
+    a ``WrappingPathway`` will intersect other objects to ensure that the path
+    between its two ends (its attachments) is the shortest possible.
+
+    To explain the sign conventions used for pathway length, extension
+    velocity, and direction of applied forces, we can ignore the geometry with
+    which the wrapping pathway interacts. A wrapping pathway is made up of two
+    points that can move relative to each other, and a pair of equal and
+    opposite forces acting on the points. If the positive time-varying
+    Euclidean distance between the two points is defined, then the "extension
+    velocity" is the time derivative of this distance. The extension velocity
+    is positive when the two points are moving away from each other and
+    negative when moving closer to each other. The direction for the force
+    acting on either point is determined by constructing a unit vector directed
+    from the other point to this point. This establishes a sign convention such
+    that a positive force magnitude tends to push the points apart. The
+    following diagram shows the positive force sense and the distance between
+    the points::
+
+       P           Q
+       o<--- F --->o
+       |           |
+       |<--l(t)--->|
+
+    Examples
+    ========
+
+    >>> from sympy.physics.mechanics import WrappingPathway
+
+    To construct a wrapping pathway, like other pathways, a pair of points must
+    be passed, followed by an instance of a wrapping geometry class as a
+    keyword argument. We'll use a cylinder with radius ``r`` and its axis
+    parallel to ``N.x`` passing through a point ``pO``.
+
+    >>> from sympy import symbols
+    >>> from sympy.physics.mechanics import Point, ReferenceFrame, WrappingCylinder
+    >>> r = symbols('r')
+    >>> N = ReferenceFrame('N')
+    >>> pA, pB, pO = Point('pA'), Point('pB'), Point('pO')
+    >>> cylinder = WrappingCylinder(r, pO, N.x)
+    >>> wrapping_pathway = WrappingPathway(pA, pB, cylinder)
+    >>> wrapping_pathway
+    WrappingPathway(pA, pB, geometry=WrappingCylinder(radius=r, point=pO,
+        axis=N.x))
+
+    Parameters
+    ==========
+
+    attachment_1 : Point
+        First of the pair of ``Point`` objects between which the wrapping
+        pathway spans.
+    attachment_2 : Point
+        Second of the pair of ``Point`` objects between which the wrapping
+        pathway spans.
+    geometry : WrappingGeometryBase
+        Geometry about which the pathway wraps.
+
+    """
+
+    def __init__(self, attachment_1, attachment_2, geometry):
+        """Initializer for ``WrappingPathway``.
+
+        Parameters
+        ==========
+
+        attachment_1 : Point
+            First of the pair of ``Point`` objects between which the wrapping
+            pathway spans.
+        attachment_2 : Point
+            Second of the pair of ``Point`` objects between which the wrapping
+            pathway spans.
+        geometry : WrappingGeometryBase
+            Geometry about which the pathway wraps.
+            The geometry about which the pathway wraps.
+
+        """
+        super().__init__(attachment_1, attachment_2)
+        self.geometry = geometry
+
+    @property
+    def geometry(self):
+        """Geometry around which the pathway wraps."""
+        return self._geometry
+
+    @geometry.setter
+    def geometry(self, geometry):
+        if hasattr(self, '_geometry'):
+            msg = (
+                f'Can\'t set attribute `geometry` to {repr(geometry)} as it '
+                f'is immutable.'
+            )
+            raise AttributeError(msg)
+        if not isinstance(geometry, WrappingGeometryBase):
+            msg = (
+                f'Value {repr(geometry)} passed to `geometry` was of type '
+                f'{type(geometry)}, must be {WrappingGeometryBase}.'
+            )
+            raise TypeError(msg)
+        self._geometry = geometry
+
+    @property
+    def length(self):
+        """Exact analytical expression for the pathway's length."""
+        return self.geometry.geodesic_length(*self.attachments)
+
+    @property
+    def extension_velocity(self):
+        """Exact analytical expression for the pathway's extension velocity."""
+        return self.length.diff(dynamicsymbols._t)
+
+    def to_loads(self, force):
+        """Loads required by the equations of motion method classes.
+
+        Explanation
+        ===========
+
+        ``KanesMethod`` requires a list of ``Point``-``Vector`` tuples to be
+        passed to the ``loads`` parameters of its ``kanes_equations`` method
+        when constructing the equations of motion. This method acts as a
+        utility to produce the correctly-structred pairs of points and vectors
+        required so that these can be easily concatenated with other items in
+        the list of loads and passed to ``KanesMethod.kanes_equations``. These
+        loads are also in the correct form to also be passed to the other
+        equations of motion method classes, e.g. ``LagrangesMethod``.
+
+        Examples
+        ========
+
+        The below example shows how to generate the loads produced in an
+        actuator that produces an expansile force ``F`` while wrapping around a
+        cylinder. First, create a cylinder with radius ``r`` and an axis
+        parallel to the ``N.z`` direction of the global frame ``N`` that also
+        passes through a point ``pO``.
+
+        >>> from sympy import symbols
+        >>> from sympy.physics.mechanics import (Point, ReferenceFrame,
+        ...     WrappingCylinder)
+        >>> N = ReferenceFrame('N')
+        >>> r = symbols('r', positive=True)
+        >>> pO = Point('pO')
+        >>> cylinder = WrappingCylinder(r, pO, N.z)
+
+        Create the pathway of the actuator using the ``WrappingPathway`` class,
+        defined to span between two points ``pA`` and ``pB``. Both points lie
+        on the surface of the cylinder and the location of ``pB`` is defined
+        relative to ``pA`` by the dynamics symbol ``q``.
+
+        >>> from sympy import cos, sin
+        >>> from sympy.physics.mechanics import WrappingPathway, dynamicsymbols
+        >>> q = dynamicsymbols('q')
+        >>> pA = Point('pA')
+        >>> pB = Point('pB')
+        >>> pA.set_pos(pO, r*N.x)
+        >>> pB.set_pos(pO, r*(cos(q)*N.x + sin(q)*N.y))
+        >>> pB.pos_from(pA)
+        (r*cos(q(t)) - r)*N.x + r*sin(q(t))*N.y
+        >>> pathway = WrappingPathway(pA, pB, cylinder)
+
+        Now create a symbol ``F`` to describe the magnitude of the (expansile)
+        force that will be produced along the pathway. The list of loads that
+        ``KanesMethod`` requires can be produced by calling the pathway's
+        ``to_loads`` method with ``F`` passed as the only argument.
+
+        >>> F = symbols('F')
+        >>> loads = pathway.to_loads(F)
+        >>> [load.__class__(load.location, load.vector.simplify()) for load in loads]
+        [(pA, F*N.y), (pB, F*sin(q(t))*N.x - F*cos(q(t))*N.y),
+         (pO, - F*sin(q(t))*N.x + F*(cos(q(t)) - 1)*N.y)]
+
+        Parameters
+        ==========
+
+        force : Expr
+            Magnitude of the force acting along the length of the pathway. It
+            is assumed that this ``Expr`` represents an expansile force.
+
+        """
+        pA, pB = self.attachments
+        pO = self.geometry.point
+        pA_force, pB_force = self.geometry.geodesic_end_vectors(pA, pB)
+        pO_force = -(pA_force + pB_force)
+
+        loads = [
+            Force(pA, force * pA_force),
+            Force(pB, force * pB_force),
+            Force(pO, force * pO_force),
+        ]
+        return loads
+
+    def __repr__(self):
+        """Representation of a ``WrappingPathway``."""
+        attachments = ', '.join(str(a) for a in self.attachments)
+        return (
+            f'{self.__class__.__name__}({attachments}, '
+            f'geometry={self.geometry})'
+        )
+
+
+def _point_pair_relative_position(point_1, point_2):
+    """The relative position between a pair of points."""
+    return point_2.pos_from(point_1)
+
+
+def _point_pair_length(point_1, point_2):
+    """The length of the direct linear path between two points."""
+    return _point_pair_relative_position(point_1, point_2).magnitude()
+
+
+def _point_pair_extension_velocity(point_1, point_2):
+    """The extension velocity of the direct linear path between two points."""
+    return _point_pair_length(point_1, point_2).diff(dynamicsymbols._t)

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/rigidbody.py

@@ -0,0 +1,314 @@
+from sympy import Symbol, S
+from sympy.physics.vector import ReferenceFrame, Dyadic, Point, dot
+from sympy.physics.mechanics.body_base import BodyBase
+from sympy.physics.mechanics.inertia import inertia_of_point_mass, Inertia
+from sympy.utilities.exceptions import sympy_deprecation_warning
+
+__all__ = ['RigidBody']
+
+
+class RigidBody(BodyBase):
+    """An idealized rigid body.
+
+    Explanation
+    ===========
+
+    This is essentially a container which holds the various components which
+    describe a rigid body: a name, mass, center of mass, reference frame, and
+    inertia.
+
+    All of these need to be supplied on creation, but can be changed
+    afterwards.
+
+    Attributes
+    ==========
+
+    name : string
+        The body's name.
+    masscenter : Point
+        The point which represents the center of mass of the rigid body.
+    frame : ReferenceFrame
+        The ReferenceFrame which the rigid body is fixed in.
+    mass : Sympifyable
+        The body's mass.
+    inertia : (Dyadic, Point)
+        The body's inertia about a point; stored in a tuple as shown above.
+    potential_energy : Sympifyable
+        The potential energy of the RigidBody.
+
+    Examples
+    ========
+
+    >>> from sympy import Symbol
+    >>> from sympy.physics.mechanics import ReferenceFrame, Point, RigidBody
+    >>> from sympy.physics.mechanics import outer
+    >>> m = Symbol('m')
+    >>> A = ReferenceFrame('A')
+    >>> P = Point('P')
+    >>> I = outer (A.x, A.x)
+    >>> inertia_tuple = (I, P)
+    >>> B = RigidBody('B', P, A, m, inertia_tuple)
+    >>> # Or you could change them afterwards
+    >>> m2 = Symbol('m2')
+    >>> B.mass = m2
+
+    """
+
+    def __init__(self, name, masscenter=None, frame=None, mass=None,
+                 inertia=None):
+        super().__init__(name, masscenter, mass)
+        if frame is None:
+            frame = ReferenceFrame(f'{name}_frame')
+        self.frame = frame
+        if inertia is None:
+            ixx = Symbol(f'{name}_ixx')
+            iyy = Symbol(f'{name}_iyy')
+            izz = Symbol(f'{name}_izz')
+            izx = Symbol(f'{name}_izx')
+            ixy = Symbol(f'{name}_ixy')
+            iyz = Symbol(f'{name}_iyz')
+            inertia = Inertia.from_inertia_scalars(self.masscenter, self.frame,
+                                                   ixx, iyy, izz, ixy, iyz, izx)
+        self.inertia = inertia
+
+    def __repr__(self):
+        return (f'{self.__class__.__name__}({repr(self.name)}, masscenter='
+                f'{repr(self.masscenter)}, frame={repr(self.frame)}, mass='
+                f'{repr(self.mass)}, inertia={repr(self.inertia)})')
+
+    @property
+    def frame(self):
+        """The ReferenceFrame fixed to the body."""
+        return self._frame
+
+    @frame.setter
+    def frame(self, F):
+        if not isinstance(F, ReferenceFrame):
+            raise TypeError("RigidBody frame must be a ReferenceFrame object.")
+        self._frame = F
+
+    @property
+    def x(self):
+        """The basis Vector for the body, in the x direction. """
+        return self.frame.x
+
+    @property
+    def y(self):
+        """The basis Vector for the body, in the y direction. """
+        return self.frame.y
+
+    @property
+    def z(self):
+        """The basis Vector for the body, in the z direction. """
+        return self.frame.z
+
+    @property
+    def inertia(self):
+        """The body's inertia about a point; stored as (Dyadic, Point)."""
+        return self._inertia
+
+    @inertia.setter
+    def inertia(self, I):
+        # check if I is of the form (Dyadic, Point)
+        if len(I) != 2 or not isinstance(I[0], Dyadic) or not isinstance(I[1], Point):
+            raise TypeError("RigidBody inertia must be a tuple of the form (Dyadic, Point).")
+
+        self._inertia = Inertia(I[0], I[1])
+        # have I S/O, want I S/S*
+        # I S/O = I S/S* + I S*/O; I S/S* = I S/O - I S*/O
+        # I_S/S* = I_S/O - I_S*/O
+        I_Ss_O = inertia_of_point_mass(self.mass,
+                                       self.masscenter.pos_from(I[1]),
+                                       self.frame)
+        self._central_inertia = I[0] - I_Ss_O
+
+    @property
+    def central_inertia(self):
+        """The body's central inertia dyadic."""
+        return self._central_inertia
+
+    @central_inertia.setter
+    def central_inertia(self, I):
+        if not isinstance(I, Dyadic):
+            raise TypeError("RigidBody inertia must be a Dyadic object.")
+        self.inertia = Inertia(I, self.masscenter)
+
+    def linear_momentum(self, frame):
+        """ Linear momentum of the rigid body.
+
+        Explanation
+        ===========
+
+        The linear momentum L, of a rigid body B, with respect to frame N is
+        given by:
+
+        ``L = m * v``
+
+        where m is the mass of the rigid body, and v is the velocity of the mass
+        center of B in the frame N.
+
+        Parameters
+        ==========
+
+        frame : ReferenceFrame
+            The frame in which linear momentum is desired.
+
+        Examples
+        ========
+
+        >>> from sympy.physics.mechanics import Point, ReferenceFrame, outer
+        >>> from sympy.physics.mechanics import RigidBody, dynamicsymbols
+        >>> from sympy.physics.vector import init_vprinting
+        >>> init_vprinting(pretty_print=False)
+        >>> m, v = dynamicsymbols('m v')
+        >>> N = ReferenceFrame('N')
+        >>> P = Point('P')
+        >>> P.set_vel(N, v * N.x)
+        >>> I = outer (N.x, N.x)
+        >>> Inertia_tuple = (I, P)
+        >>> B = RigidBody('B', P, N, m, Inertia_tuple)
+        >>> B.linear_momentum(N)
+        m*v*N.x
+
+        """
+
+        return self.mass * self.masscenter.vel(frame)
+
+    def angular_momentum(self, point, frame):
+        """Returns the angular momentum of the rigid body about a point in the
+        given frame.
+
+        Explanation
+        ===========
+
+        The angular momentum H of a rigid body B about some point O in a frame N
+        is given by:
+
+        ``H = dot(I, w) + cross(r, m * v)``
+
+        where I and m are the central inertia dyadic and mass of rigid body B, w
+        is the angular velocity of body B in the frame N, r is the position
+        vector from point O to the mass center of B, and v is the velocity of
+        the mass center in the frame N.
+
+        Parameters
+        ==========
+
+        point : Point
+            The point about which angular momentum is desired.
+        frame : ReferenceFrame
+            The frame in which angular momentum is desired.
+
+        Examples
+        ========
+
+        >>> from sympy.physics.mechanics import Point, ReferenceFrame, outer
+        >>> from sympy.physics.mechanics import RigidBody, dynamicsymbols
+        >>> from sympy.physics.vector import init_vprinting
+        >>> init_vprinting(pretty_print=False)
+        >>> m, v, r, omega = dynamicsymbols('m v r omega')
+        >>> N = ReferenceFrame('N')
+        >>> b = ReferenceFrame('b')
+        >>> b.set_ang_vel(N, omega * b.x)
+        >>> P = Point('P')
+        >>> P.set_vel(N, 1 * N.x)
+        >>> I = outer(b.x, b.x)
+        >>> B = RigidBody('B', P, b, m, (I, P))
+        >>> B.angular_momentum(P, N)
+        omega*b.x
+
+        """
+        I = self.central_inertia
+        w = self.frame.ang_vel_in(frame)
+        m = self.mass
+        r = self.masscenter.pos_from(point)
+        v = self.masscenter.vel(frame)
+
+        return I.dot(w) + r.cross(m * v)
+
+    def kinetic_energy(self, frame):
+        """Kinetic energy of the rigid body.
+
+        Explanation
+        ===========
+
+        The kinetic energy, T, of a rigid body, B, is given by:
+
+        ``T = 1/2 * (dot(dot(I, w), w) + dot(m * v, v))``
+
+        where I and m are the central inertia dyadic and mass of rigid body B
+        respectively, w is the body's angular velocity, and v is the velocity of
+        the body's mass center in the supplied ReferenceFrame.
+
+        Parameters
+        ==========
+
+        frame : ReferenceFrame
+            The RigidBody's angular velocity and the velocity of it's mass
+            center are typically defined with respect to an inertial frame but
+            any relevant frame in which the velocities are known can be
+            supplied.
+
+        Examples
+        ========
+
+        >>> from sympy.physics.mechanics import Point, ReferenceFrame, outer
+        >>> from sympy.physics.mechanics import RigidBody
+        >>> from sympy import symbols
+        >>> m, v, r, omega = symbols('m v r omega')
+        >>> N = ReferenceFrame('N')
+        >>> b = ReferenceFrame('b')
+        >>> b.set_ang_vel(N, omega * b.x)
+        >>> P = Point('P')
+        >>> P.set_vel(N, v * N.x)
+        >>> I = outer (b.x, b.x)
+        >>> inertia_tuple = (I, P)
+        >>> B = RigidBody('B', P, b, m, inertia_tuple)
+        >>> B.kinetic_energy(N)
+        m*v**2/2 + omega**2/2
+
+        """
+
+        rotational_KE = S.Half * dot(
+            self.frame.ang_vel_in(frame),
+            dot(self.central_inertia, self.frame.ang_vel_in(frame)))
+        translational_KE = S.Half * self.mass * dot(self.masscenter.vel(frame),
+                                                    self.masscenter.vel(frame))
+        return rotational_KE + translational_KE
+
+    def set_potential_energy(self, scalar):
+        sympy_deprecation_warning(
+            """
+The sympy.physics.mechanics.RigidBody.set_potential_energy()
+method is deprecated. Instead use
+
+    B.potential_energy = scalar
+            """,
+        deprecated_since_version="1.5",
+        active_deprecations_target="deprecated-set-potential-energy",
+        )
+        self.potential_energy = scalar
+
+    def parallel_axis(self, point, frame=None):
+        """Returns the inertia dyadic of the body with respect to another point.
+
+        Parameters
+        ==========
+
+        point : sympy.physics.vector.Point
+            The point to express the inertia dyadic about.
+        frame : sympy.physics.vector.ReferenceFrame
+            The reference frame used to construct the dyadic.
+
+        Returns
+        =======
+
+        inertia : sympy.physics.vector.Dyadic
+            The inertia dyadic of the rigid body expressed about the provided
+            point.
+
+        """
+        if frame is None:
+            frame = self.frame
+        return self.central_inertia + inertia_of_point_mass(
+            self.mass, self.masscenter.pos_from(point), frame)

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_actuator.py

@@ -0,0 +1,851 @@
+"""Tests for the ``sympy.physics.mechanics.actuator.py`` module."""
+
+import pytest
+
+from sympy import (
+    S,
+    Matrix,
+    Symbol,
+    SympifyError,
+    sqrt,
+    Abs
+)
+from sympy.physics.mechanics import (
+    ActuatorBase,
+    Force,
+    ForceActuator,
+    KanesMethod,
+    LinearDamper,
+    LinearPathway,
+    LinearSpring,
+    Particle,
+    PinJoint,
+    Point,
+    ReferenceFrame,
+    RigidBody,
+    TorqueActuator,
+    Vector,
+    dynamicsymbols,
+    DuffingSpring,
+)
+
+from sympy.core.expr import Expr as ExprType
+
+target = RigidBody('target')
+reaction = RigidBody('reaction')
+
+
+class TestForceActuator:
+
+    @pytest.fixture(autouse=True)
+    def _linear_pathway_fixture(self):
+        self.force = Symbol('F')
+        self.pA = Point('pA')
+        self.pB = Point('pB')
+        self.pathway = LinearPathway(self.pA, self.pB)
+        self.q1 = dynamicsymbols('q1')
+        self.q2 = dynamicsymbols('q2')
+        self.q3 = dynamicsymbols('q3')
+        self.q1d = dynamicsymbols('q1', 1)
+        self.q2d = dynamicsymbols('q2', 1)
+        self.q3d = dynamicsymbols('q3', 1)
+        self.N = ReferenceFrame('N')
+
+    def test_is_actuator_base_subclass(self):
+        assert issubclass(ForceActuator, ActuatorBase)
+
+    @pytest.mark.parametrize(
+        'force, expected_force',
+        [
+            (1, S.One),
+            (S.One, S.One),
+            (Symbol('F'), Symbol('F')),
+            (dynamicsymbols('F'), dynamicsymbols('F')),
+            (Symbol('F')**2 + Symbol('F'), Symbol('F')**2 + Symbol('F')),
+        ]
+    )
+    def test_valid_constructor_force(self, force, expected_force):
+        instance = ForceActuator(force, self.pathway)
+        assert isinstance(instance, ForceActuator)
+        assert hasattr(instance, 'force')
+        assert isinstance(instance.force, ExprType)
+        assert instance.force == expected_force
+
+    @pytest.mark.parametrize('force', [None, 'F'])
+    def test_invalid_constructor_force_not_sympifyable(self, force):
+        with pytest.raises(SympifyError):
+            _ = ForceActuator(force, self.pathway)
+
+    @pytest.mark.parametrize(
+        'pathway',
+        [
+            LinearPathway(Point('pA'), Point('pB')),
+        ]
+    )
+    def test_valid_constructor_pathway(self, pathway):
+        instance = ForceActuator(self.force, pathway)
+        assert isinstance(instance, ForceActuator)
+        assert hasattr(instance, 'pathway')
+        assert isinstance(instance.pathway, LinearPathway)
+        assert instance.pathway == pathway
+
+    def test_invalid_constructor_pathway_not_pathway_base(self):
+        with pytest.raises(TypeError):
+            _ = ForceActuator(self.force, None)
+
+    @pytest.mark.parametrize(
+        'property_name, fixture_attr_name',
+        [
+            ('force', 'force'),
+            ('pathway', 'pathway'),
+        ]
+    )
+    def test_properties_are_immutable(self, property_name, fixture_attr_name):
+        instance = ForceActuator(self.force, self.pathway)
+        value = getattr(self, fixture_attr_name)
+        with pytest.raises(AttributeError):
+            setattr(instance, property_name, value)
+
+    def test_repr(self):
+        actuator = ForceActuator(self.force, self.pathway)
+        expected = "ForceActuator(F, LinearPathway(pA, pB))"
+        assert repr(actuator) == expected
+
+    def test_to_loads_static_pathway(self):
+        self.pB.set_pos(self.pA, 2*self.N.x)
+        actuator = ForceActuator(self.force, self.pathway)
+        expected = [
+            (self.pA, - self.force*self.N.x),
+            (self.pB, self.force*self.N.x),
+        ]
+        assert actuator.to_loads() == expected
+
+    def test_to_loads_2D_pathway(self):
+        self.pB.set_pos(self.pA, 2*self.q1*self.N.x)
+        actuator = ForceActuator(self.force, self.pathway)
+        expected = [
+            (self.pA, - self.force*(self.q1/sqrt(self.q1**2))*self.N.x),
+            (self.pB, self.force*(self.q1/sqrt(self.q1**2))*self.N.x),
+        ]
+        assert actuator.to_loads() == expected
+
+    def test_to_loads_3D_pathway(self):
+        self.pB.set_pos(
+            self.pA,
+            self.q1*self.N.x - self.q2*self.N.y + 2*self.q3*self.N.z,
+        )
+        actuator = ForceActuator(self.force, self.pathway)
+        length = sqrt(self.q1**2 + self.q2**2 + 4*self.q3**2)
+        pO_force = (
+            - self.force*self.q1*self.N.x/length
+            + self.force*self.q2*self.N.y/length
+            - 2*self.force*self.q3*self.N.z/length
+        )
+        pI_force = (
+            self.force*self.q1*self.N.x/length
+            - self.force*self.q2*self.N.y/length
+            + 2*self.force*self.q3*self.N.z/length
+        )
+        expected = [
+            (self.pA, pO_force),
+            (self.pB, pI_force),
+        ]
+        assert actuator.to_loads() == expected
+
+
+class TestLinearSpring:
+
+    @pytest.fixture(autouse=True)
+    def _linear_spring_fixture(self):
+        self.stiffness = Symbol('k')
+        self.l = Symbol('l')
+        self.pA = Point('pA')
+        self.pB = Point('pB')
+        self.pathway = LinearPathway(self.pA, self.pB)
+        self.q = dynamicsymbols('q')
+        self.N = ReferenceFrame('N')
+
+    def test_is_force_actuator_subclass(self):
+        assert issubclass(LinearSpring, ForceActuator)
+
+    def test_is_actuator_base_subclass(self):
+        assert issubclass(LinearSpring, ActuatorBase)
+
+    @pytest.mark.parametrize(
+        (
+            'stiffness, '
+            'expected_stiffness, '
+            'equilibrium_length, '
+            'expected_equilibrium_length, '
+            'force'
+        ),
+        [
+            (
+                1,
+                S.One,
+                0,
+                S.Zero,
+                -sqrt(dynamicsymbols('q')**2),
+            ),
+            (
+                Symbol('k'),
+                Symbol('k'),
+                0,
+                S.Zero,
+                -Symbol('k')*sqrt(dynamicsymbols('q')**2),
+            ),
+            (
+                Symbol('k'),
+                Symbol('k'),
+                S.Zero,
+                S.Zero,
+                -Symbol('k')*sqrt(dynamicsymbols('q')**2),
+            ),
+            (
+                Symbol('k'),
+                Symbol('k'),
+                Symbol('l'),
+                Symbol('l'),
+                -Symbol('k')*(sqrt(dynamicsymbols('q')**2) - Symbol('l')),
+            ),
+        ]
+    )
+    def test_valid_constructor(
+        self,
+        stiffness,
+        expected_stiffness,
+        equilibrium_length,
+        expected_equilibrium_length,
+        force,
+    ):
+        self.pB.set_pos(self.pA, self.q*self.N.x)
+        spring = LinearSpring(stiffness, self.pathway, equilibrium_length)
+
+        assert isinstance(spring, LinearSpring)
+
+        assert hasattr(spring, 'stiffness')
+        assert isinstance(spring.stiffness, ExprType)
+        assert spring.stiffness == expected_stiffness
+
+        assert hasattr(spring, 'pathway')
+        assert isinstance(spring.pathway, LinearPathway)
+        assert spring.pathway == self.pathway
+
+        assert hasattr(spring, 'equilibrium_length')
+        assert isinstance(spring.equilibrium_length, ExprType)
+        assert spring.equilibrium_length == expected_equilibrium_length
+
+        assert hasattr(spring, 'force')
+        assert isinstance(spring.force, ExprType)
+        assert spring.force == force
+
+    @pytest.mark.parametrize('stiffness', [None, 'k'])
+    def test_invalid_constructor_stiffness_not_sympifyable(self, stiffness):
+        with pytest.raises(SympifyError):
+            _ = LinearSpring(stiffness, self.pathway, self.l)
+
+    def test_invalid_constructor_pathway_not_pathway_base(self):
+        with pytest.raises(TypeError):
+            _ = LinearSpring(self.stiffness, None, self.l)
+
+    @pytest.mark.parametrize('equilibrium_length', [None, 'l'])
+    def test_invalid_constructor_equilibrium_length_not_sympifyable(
+        self,
+        equilibrium_length,
+    ):
+        with pytest.raises(SympifyError):
+            _ = LinearSpring(self.stiffness, self.pathway, equilibrium_length)
+
+    @pytest.mark.parametrize(
+        'property_name, fixture_attr_name',
+        [
+            ('stiffness', 'stiffness'),
+            ('pathway', 'pathway'),
+            ('equilibrium_length', 'l'),
+        ]
+    )
+    def test_properties_are_immutable(self, property_name, fixture_attr_name):
+        spring = LinearSpring(self.stiffness, self.pathway, self.l)
+        value = getattr(self, fixture_attr_name)
+        with pytest.raises(AttributeError):
+            setattr(spring, property_name, value)
+
+    @pytest.mark.parametrize(
+        'equilibrium_length, expected',
+        [
+            (S.Zero, 'LinearSpring(k, LinearPathway(pA, pB))'),
+            (
+                Symbol('l'),
+                'LinearSpring(k, LinearPathway(pA, pB), equilibrium_length=l)',
+            ),
+        ]
+    )
+    def test_repr(self, equilibrium_length, expected):
+        self.pB.set_pos(self.pA, self.q*self.N.x)
+        spring = LinearSpring(self.stiffness, self.pathway, equilibrium_length)
+        assert repr(spring) == expected
+
+    def test_to_loads(self):
+        self.pB.set_pos(self.pA, self.q*self.N.x)
+        spring = LinearSpring(self.stiffness, self.pathway, self.l)
+        normal = self.q/sqrt(self.q**2)*self.N.x
+        pA_force = self.stiffness*(sqrt(self.q**2) - self.l)*normal
+        pB_force = -self.stiffness*(sqrt(self.q**2) - self.l)*normal
+        expected = [Force(self.pA, pA_force), Force(self.pB, pB_force)]
+        loads = spring.to_loads()
+
+        for load, (point, vector) in zip(loads, expected):
+            assert isinstance(load, Force)
+            assert load.point == point
+            assert (load.vector - vector).simplify() == 0
+
+
+class TestLinearDamper:
+
+    @pytest.fixture(autouse=True)
+    def _linear_damper_fixture(self):
+        self.damping = Symbol('c')
+        self.l = Symbol('l')
+        self.pA = Point('pA')
+        self.pB = Point('pB')
+        self.pathway = LinearPathway(self.pA, self.pB)
+        self.q = dynamicsymbols('q')
+        self.dq = dynamicsymbols('q', 1)
+        self.u = dynamicsymbols('u')
+        self.N = ReferenceFrame('N')
+
+    def test_is_force_actuator_subclass(self):
+        assert issubclass(LinearDamper, ForceActuator)
+
+    def test_is_actuator_base_subclass(self):
+        assert issubclass(LinearDamper, ActuatorBase)
+
+    def test_valid_constructor(self):
+        self.pB.set_pos(self.pA, self.q*self.N.x)
+        damper = LinearDamper(self.damping, self.pathway)
+
+        assert isinstance(damper, LinearDamper)
+
+        assert hasattr(damper, 'damping')
+        assert isinstance(damper.damping, ExprType)
+        assert damper.damping == self.damping
+
+        assert hasattr(damper, 'pathway')
+        assert isinstance(damper.pathway, LinearPathway)
+        assert damper.pathway == self.pathway
+
+    def test_valid_constructor_force(self):
+        self.pB.set_pos(self.pA, self.q*self.N.x)
+        damper = LinearDamper(self.damping, self.pathway)
+
+        expected_force = -self.damping*sqrt(self.q**2)*self.dq/self.q
+        assert hasattr(damper, 'force')
+        assert isinstance(damper.force, ExprType)
+        assert damper.force == expected_force
+
+    @pytest.mark.parametrize('damping', [None, 'c'])
+    def test_invalid_constructor_damping_not_sympifyable(self, damping):
+        with pytest.raises(SympifyError):
+            _ = LinearDamper(damping, self.pathway)
+
+    def test_invalid_constructor_pathway_not_pathway_base(self):
+        with pytest.raises(TypeError):
+            _ = LinearDamper(self.damping, None)
+
+    @pytest.mark.parametrize(
+        'property_name, fixture_attr_name',
+        [
+            ('damping', 'damping'),
+            ('pathway', 'pathway'),
+        ]
+    )
+    def test_properties_are_immutable(self, property_name, fixture_attr_name):
+        damper = LinearDamper(self.damping, self.pathway)
+        value = getattr(self, fixture_attr_name)
+        with pytest.raises(AttributeError):
+            setattr(damper, property_name, value)
+
+    def test_repr(self):
+        self.pB.set_pos(self.pA, self.q*self.N.x)
+        damper = LinearDamper(self.damping, self.pathway)
+        expected = 'LinearDamper(c, LinearPathway(pA, pB))'
+        assert repr(damper) == expected
+
+    def test_to_loads(self):
+        self.pB.set_pos(self.pA, self.q*self.N.x)
+        damper = LinearDamper(self.damping, self.pathway)
+        direction = self.q**2/self.q**2*self.N.x
+        pA_force = self.damping*self.dq*direction
+        pB_force = -self.damping*self.dq*direction
+        expected = [Force(self.pA, pA_force), Force(self.pB, pB_force)]
+        assert damper.to_loads() == expected
+
+
+class TestForcedMassSpringDamperModel():
+    r"""A single degree of freedom translational forced mass-spring-damper.
+
+    Notes
+    =====
+
+    This system is well known to have the governing equation:
+
+    .. math::
+        m \ddot{x} = F - k x - c \dot{x}
+
+    where $F$ is an externally applied force, $m$ is the mass of the particle
+    to which the spring and damper are attached, $k$ is the spring's stiffness,
+    $c$ is the dampers damping coefficient, and $x$ is the generalized
+    coordinate representing the system's single (translational) degree of
+    freedom.
+
+    """
+
+    @pytest.fixture(autouse=True)
+    def _force_mass_spring_damper_model_fixture(self):
+        self.m = Symbol('m')
+        self.k = Symbol('k')
+        self.c = Symbol('c')
+        self.F = Symbol('F')
+
+        self.q = dynamicsymbols('q')
+        self.dq = dynamicsymbols('q', 1)
+        self.u = dynamicsymbols('u')
+
+        self.frame = ReferenceFrame('N')
+        self.origin = Point('pO')
+        self.origin.set_vel(self.frame, 0)
+
+        self.attachment = Point('pA')
+        self.attachment.set_pos(self.origin, self.q*self.frame.x)
+
+        self.mass = Particle('mass', self.attachment, self.m)
+        self.pathway = LinearPathway(self.origin, self.attachment)
+
+        self.kanes_method = KanesMethod(
+            self.frame,
+            q_ind=[self.q],
+            u_ind=[self.u],
+            kd_eqs=[self.dq - self.u],
+        )
+        self.bodies = [self.mass]
+
+        self.mass_matrix = Matrix([[self.m]])
+        self.forcing = Matrix([[self.F - self.c*self.u - self.k*self.q]])
+
+    def test_force_acuator(self):
+        stiffness = -self.k*self.pathway.length
+        spring = ForceActuator(stiffness, self.pathway)
+        damping = -self.c*self.pathway.extension_velocity
+        damper = ForceActuator(damping, self.pathway)
+
+        loads = [
+            (self.attachment, self.F*self.frame.x),
+            *spring.to_loads(),
+            *damper.to_loads(),
+        ]
+        self.kanes_method.kanes_equations(self.bodies, loads)
+
+        assert self.kanes_method.mass_matrix == self.mass_matrix
+        assert self.kanes_method.forcing == self.forcing
+
+    def test_linear_spring_linear_damper(self):
+        spring = LinearSpring(self.k, self.pathway)
+        damper = LinearDamper(self.c, self.pathway)
+
+        loads = [
+            (self.attachment, self.F*self.frame.x),
+            *spring.to_loads(),
+            *damper.to_loads(),
+        ]
+        self.kanes_method.kanes_equations(self.bodies, loads)
+
+        assert self.kanes_method.mass_matrix == self.mass_matrix
+        assert self.kanes_method.forcing == self.forcing
+
+
+class TestTorqueActuator:
+
+    @pytest.fixture(autouse=True)
+    def _torque_actuator_fixture(self):
+        self.torque = Symbol('T')
+        self.N = ReferenceFrame('N')
+        self.A = ReferenceFrame('A')
+        self.axis = self.N.z
+        self.target = RigidBody('target', frame=self.N)
+        self.reaction = RigidBody('reaction', frame=self.A)
+
+    def test_is_actuator_base_subclass(self):
+        assert issubclass(TorqueActuator, ActuatorBase)
+
+    @pytest.mark.parametrize(
+        'torque',
+        [
+            Symbol('T'),
+            dynamicsymbols('T'),
+            Symbol('T')**2 + Symbol('T'),
+        ]
+    )
+    @pytest.mark.parametrize(
+        'target_frame, reaction_frame',
+        [
+            (target.frame, reaction.frame),
+            (target, reaction.frame),
+            (target.frame, reaction),
+            (target, reaction),
+        ]
+    )
+    def test_valid_constructor_with_reaction(
+        self,
+        torque,
+        target_frame,
+        reaction_frame,
+    ):
+        instance = TorqueActuator(
+            torque,
+            self.axis,
+            target_frame,
+            reaction_frame,
+        )
+        assert isinstance(instance, TorqueActuator)
+
+        assert hasattr(instance, 'torque')
+        assert isinstance(instance.torque, ExprType)
+        assert instance.torque == torque
+
+        assert hasattr(instance, 'axis')
+        assert isinstance(instance.axis, Vector)
+        assert instance.axis == self.axis
+
+        assert hasattr(instance, 'target_frame')
+        assert isinstance(instance.target_frame, ReferenceFrame)
+        assert instance.target_frame == target.frame
+
+        assert hasattr(instance, 'reaction_frame')
+        assert isinstance(instance.reaction_frame, ReferenceFrame)
+        assert instance.reaction_frame == reaction.frame
+
+    @pytest.mark.parametrize(
+        'torque',
+        [
+            Symbol('T'),
+            dynamicsymbols('T'),
+            Symbol('T')**2 + Symbol('T'),
+        ]
+    )
+    @pytest.mark.parametrize('target_frame', [target.frame, target])
+    def test_valid_constructor_without_reaction(self, torque, target_frame):
+        instance = TorqueActuator(torque, self.axis, target_frame)
+        assert isinstance(instance, TorqueActuator)
+
+        assert hasattr(instance, 'torque')
+        assert isinstance(instance.torque, ExprType)
+        assert instance.torque == torque
+
+        assert hasattr(instance, 'axis')
+        assert isinstance(instance.axis, Vector)
+        assert instance.axis == self.axis
+
+        assert hasattr(instance, 'target_frame')
+        assert isinstance(instance.target_frame, ReferenceFrame)
+        assert instance.target_frame == target.frame
+
+        assert hasattr(instance, 'reaction_frame')
+        assert instance.reaction_frame is None
+
+    @pytest.mark.parametrize('torque', [None, 'T'])
+    def test_invalid_constructor_torque_not_sympifyable(self, torque):
+        with pytest.raises(SympifyError):
+            _ = TorqueActuator(torque, self.axis, self.target)
+
+    @pytest.mark.parametrize('axis', [Symbol('a'), dynamicsymbols('a')])
+    def test_invalid_constructor_axis_not_vector(self, axis):
+        with pytest.raises(TypeError):
+            _ = TorqueActuator(self.torque, axis, self.target, self.reaction)
+
+    @pytest.mark.parametrize(
+        'frames',
+        [
+            (None, ReferenceFrame('child')),
+            (ReferenceFrame('parent'), True),
+            (None, RigidBody('child')),
+            (RigidBody('parent'), True),
+        ]
+    )
+    def test_invalid_constructor_frames_not_frame(self, frames):
+        with pytest.raises(TypeError):
+            _ = TorqueActuator(self.torque, self.axis, *frames)
+
+    @pytest.mark.parametrize(
+        'property_name, fixture_attr_name',
+        [
+            ('torque', 'torque'),
+            ('axis', 'axis'),
+            ('target_frame', 'target'),
+            ('reaction_frame', 'reaction'),
+        ]
+    )
+    def test_properties_are_immutable(self, property_name, fixture_attr_name):
+        actuator = TorqueActuator(
+            self.torque,
+            self.axis,
+            self.target,
+            self.reaction,
+        )
+        value = getattr(self, fixture_attr_name)
+        with pytest.raises(AttributeError):
+            setattr(actuator, property_name, value)
+
+    def test_repr_without_reaction(self):
+        actuator = TorqueActuator(self.torque, self.axis, self.target)
+        expected = 'TorqueActuator(T, axis=N.z, target_frame=N)'
+        assert repr(actuator) == expected
+
+    def test_repr_with_reaction(self):
+        actuator = TorqueActuator(
+            self.torque,
+            self.axis,
+            self.target,
+            self.reaction,
+        )
+        expected = 'TorqueActuator(T, axis=N.z, target_frame=N, reaction_frame=A)'
+        assert repr(actuator) == expected
+
+    def test_at_pin_joint_constructor(self):
+        pin_joint = PinJoint(
+            'pin',
+            self.target,
+            self.reaction,
+            coordinates=dynamicsymbols('q'),
+            speeds=dynamicsymbols('u'),
+            parent_interframe=self.N,
+            joint_axis=self.axis,
+        )
+        instance = TorqueActuator.at_pin_joint(self.torque, pin_joint)
+        assert isinstance(instance, TorqueActuator)
+
+        assert hasattr(instance, 'torque')
+        assert isinstance(instance.torque, ExprType)
+        assert instance.torque == self.torque
+
+        assert hasattr(instance, 'axis')
+        assert isinstance(instance.axis, Vector)
+        assert instance.axis == self.axis
+
+        assert hasattr(instance, 'target_frame')
+        assert isinstance(instance.target_frame, ReferenceFrame)
+        assert instance.target_frame == self.A
+
+        assert hasattr(instance, 'reaction_frame')
+        assert isinstance(instance.reaction_frame, ReferenceFrame)
+        assert instance.reaction_frame == self.N
+
+    def test_at_pin_joint_pin_joint_not_pin_joint_invalid(self):
+        with pytest.raises(TypeError):
+            _ = TorqueActuator.at_pin_joint(self.torque, Symbol('pin'))
+
+    def test_to_loads_without_reaction(self):
+        actuator = TorqueActuator(self.torque, self.axis, self.target)
+        expected = [
+            (self.N, self.torque*self.axis),
+        ]
+        assert actuator.to_loads() == expected
+
+    def test_to_loads_with_reaction(self):
+        actuator = TorqueActuator(
+            self.torque,
+            self.axis,
+            self.target,
+            self.reaction,
+        )
+        expected = [
+            (self.N, self.torque*self.axis),
+            (self.A, - self.torque*self.axis),
+        ]
+        assert actuator.to_loads() == expected
+
+
+class NonSympifyable:
+    pass
+
+
+class TestDuffingSpring:
+    @pytest.fixture(autouse=True)
+    # Set up common vairables that will be used in multiple tests
+    def _duffing_spring_fixture(self):
+        self.linear_stiffness = Symbol('beta')
+        self.nonlinear_stiffness = Symbol('alpha')
+        self.equilibrium_length = Symbol('l')
+        self.pA = Point('pA')
+        self.pB = Point('pB')
+        self.pathway = LinearPathway(self.pA, self.pB)
+        self.q = dynamicsymbols('q')
+        self.N = ReferenceFrame('N')
+
+    # Simples tests to check that DuffingSpring is a subclass of ForceActuator and ActuatorBase
+    def test_is_force_actuator_subclass(self):
+        assert issubclass(DuffingSpring, ForceActuator)
+
+    def test_is_actuator_base_subclass(self):
+        assert issubclass(DuffingSpring, ActuatorBase)
+
+    @pytest.mark.parametrize(
+    # Create parametrized tests that allows running the same test function multiple times with different sets of arguments
+    (
+        'linear_stiffness,  '
+        'expected_linear_stiffness,  '
+        'nonlinear_stiffness,   '
+        'expected_nonlinear_stiffness,  '
+        'equilibrium_length,    '
+        'expected_equilibrium_length,   '
+        'force'
+    ),
+    [
+            (
+                1,
+                S.One,
+                1,
+                S.One,
+                0,
+                S.Zero,
+                -sqrt(dynamicsymbols('q')**2)-(sqrt(dynamicsymbols('q')**2))**3,
+            ),
+            (
+                Symbol('beta'),
+                Symbol('beta'),
+                Symbol('alpha'),
+                Symbol('alpha'),
+                0,
+                S.Zero,
+                -Symbol('beta')*sqrt(dynamicsymbols('q')**2)-Symbol('alpha')*(sqrt(dynamicsymbols('q')**2))**3,
+            ),
+            (
+                Symbol('beta'),
+                Symbol('beta'),
+                Symbol('alpha'),
+                Symbol('alpha'),
+                S.Zero,
+                S.Zero,
+                -Symbol('beta')*sqrt(dynamicsymbols('q')**2)-Symbol('alpha')*(sqrt(dynamicsymbols('q')**2))**3,
+            ),
+            (
+                Symbol('beta'),
+                Symbol('beta'),
+                Symbol('alpha'),
+                Symbol('alpha'),
+                Symbol('l'),
+                Symbol('l'),
+                -Symbol('beta') * (sqrt(dynamicsymbols('q')**2) - Symbol('l')) - Symbol('alpha') * (sqrt(dynamicsymbols('q')**2) - Symbol('l'))**3,
+            ),
+        ]
+    )
+
+    # Check if DuffingSpring correctly inializes its attributes
+    # It tests various combinations of linear & nonlinear stiffness, equilibriun length, and the resulting force expression
+    def test_valid_constructor(
+        self,
+        linear_stiffness,
+        expected_linear_stiffness,
+        nonlinear_stiffness,
+        expected_nonlinear_stiffness,
+        equilibrium_length,
+        expected_equilibrium_length,
+        force,
+    ):
+        self.pB.set_pos(self.pA, self.q*self.N.x)
+        spring = DuffingSpring(linear_stiffness, nonlinear_stiffness, self.pathway, equilibrium_length)
+
+        assert isinstance(spring, DuffingSpring)
+
+        assert hasattr(spring, 'linear_stiffness')
+        assert isinstance(spring.linear_stiffness, ExprType)
+        assert spring.linear_stiffness == expected_linear_stiffness
+
+        assert hasattr(spring, 'nonlinear_stiffness')
+        assert isinstance(spring.nonlinear_stiffness, ExprType)
+        assert spring.nonlinear_stiffness == expected_nonlinear_stiffness
+
+        assert hasattr(spring, 'pathway')
+        assert isinstance(spring.pathway, LinearPathway)
+        assert spring.pathway == self.pathway
+
+        assert hasattr(spring, 'equilibrium_length')
+        assert isinstance(spring.equilibrium_length, ExprType)
+        assert spring.equilibrium_length == expected_equilibrium_length
+
+        assert hasattr(spring, 'force')
+        assert isinstance(spring.force, ExprType)
+        assert spring.force == force
+
+    @pytest.mark.parametrize('linear_stiffness', [None, NonSympifyable()])
+    def test_invalid_constructor_linear_stiffness_not_sympifyable(self, linear_stiffness):
+        with pytest.raises(SympifyError):
+            _ = DuffingSpring(linear_stiffness, self.nonlinear_stiffness, self.pathway, self.equilibrium_length)
+
+    @pytest.mark.parametrize('nonlinear_stiffness', [None, NonSympifyable()])
+    def test_invalid_constructor_nonlinear_stiffness_not_sympifyable(self, nonlinear_stiffness):
+        with pytest.raises(SympifyError):
+            _ = DuffingSpring(self.linear_stiffness, nonlinear_stiffness, self.pathway, self.equilibrium_length)
+
+    def test_invalid_constructor_pathway_not_pathway_base(self):
+        with pytest.raises(TypeError):
+            _ = DuffingSpring(self.linear_stiffness, self.nonlinear_stiffness, NonSympifyable(), self.equilibrium_length)
+
+    @pytest.mark.parametrize('equilibrium_length', [None, NonSympifyable()])
+    def test_invalid_constructor_equilibrium_length_not_sympifyable(self, equilibrium_length):
+        with pytest.raises(SympifyError):
+            _ = DuffingSpring(self.linear_stiffness, self.nonlinear_stiffness, self.pathway, equilibrium_length)
+
+    @pytest.mark.parametrize(
+        'property_name, fixture_attr_name',
+        [
+            ('linear_stiffness', 'linear_stiffness'),
+            ('nonlinear_stiffness', 'nonlinear_stiffness'),
+            ('pathway', 'pathway'),
+            ('equilibrium_length', 'equilibrium_length')
+        ]
+    )
+    # Check if certain properties of DuffingSpring object are immutable after initialization
+    # Ensure that once DuffingSpring is created, its key properties cannot be changed
+    def test_properties_are_immutable(self, property_name, fixture_attr_name):
+        spring = DuffingSpring(self.linear_stiffness, self.nonlinear_stiffness, self.pathway, self.equilibrium_length)
+        with pytest.raises(AttributeError):
+            setattr(spring, property_name, getattr(self, fixture_attr_name))
+
+    @pytest.mark.parametrize(
+        'equilibrium_length, expected',
+        [
+            (0, 'DuffingSpring(beta, alpha, LinearPathway(pA, pB), equilibrium_length=0)'),
+            (Symbol('l'), 'DuffingSpring(beta, alpha, LinearPathway(pA, pB), equilibrium_length=l)'),
+        ]
+    )
+    # Check the __repr__ method of DuffingSpring class
+    # Check if the actual string representation of DuffingSpring instance matches the expected string for each provided parameter values
+    def test_repr(self, equilibrium_length, expected):
+        spring = DuffingSpring(self.linear_stiffness, self.nonlinear_stiffness, self.pathway, equilibrium_length)
+        assert repr(spring) == expected
+
+    def test_to_loads(self):
+        self.pB.set_pos(self.pA, self.q*self.N.x)
+        spring = DuffingSpring(self.linear_stiffness, self.nonlinear_stiffness, self.pathway, self.equilibrium_length)
+
+        # Calculate the displacement from the equilibrium length
+        displacement = self.q - self.equilibrium_length
+
+        # Make sure this matches the computation in DuffingSpring class
+        force = -self.linear_stiffness * displacement - self.nonlinear_stiffness * displacement**3
+
+        # The expected loads on pA and pB due to the spring
+        expected_loads = [Force(self.pA, force * self.N.x), Force(self.pB, -force * self.N.x)]
+
+        # Compare expected loads to what is returned from DuffingSpring.to_loads()
+        calculated_loads = spring.to_loads()
+        for calculated, expected in zip(calculated_loads, expected_loads):
+            assert calculated.point == expected.point
+            for dim in self.N:  # Assuming self.N is the reference frame
+                calculated_component = calculated.vector.dot(dim)
+                expected_component = expected.vector.dot(dim)
+                # Substitute all symbols with numeric values
+                substitutions = {self.q: 1, Symbol('l'): 1, Symbol('alpha'): 1, Symbol('beta'): 1}  # Add other necessary symbols as needed
+                diff = (calculated_component - expected_component).subs(substitutions).evalf()
+                # Check if the absolute value of the difference is below a threshold
+                assert Abs(diff) < 1e-9, f"The forces do not match. Difference: {diff}"

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_functions.py

@@ -0,0 +1,262 @@
+from sympy import sin, cos, tan, pi, symbols, Matrix, S, Function
+from sympy.physics.mechanics import (Particle, Point, ReferenceFrame,
+                                     RigidBody)
+from sympy.physics.mechanics import (angular_momentum, dynamicsymbols,
+                                     kinetic_energy, linear_momentum,
+                                     outer, potential_energy, msubs,
+                                     find_dynamicsymbols, Lagrangian)
+
+from sympy.physics.mechanics.functions import (
+    center_of_mass, _validate_coordinates, _parse_linear_solver)
+from sympy.testing.pytest import raises, warns_deprecated_sympy
+
+
+q1, q2, q3, q4, q5 = symbols('q1 q2 q3 q4 q5')
+N = ReferenceFrame('N')
+A = N.orientnew('A', 'Axis', [q1, N.z])
+B = A.orientnew('B', 'Axis', [q2, A.x])
+C = B.orientnew('C', 'Axis', [q3, B.y])
+
+
+def test_linear_momentum():
+    N = ReferenceFrame('N')
+    Ac = Point('Ac')
+    Ac.set_vel(N, 25 * N.y)
+    I = outer(N.x, N.x)
+    A = RigidBody('A', Ac, N, 20, (I, Ac))
+    P = Point('P')
+    Pa = Particle('Pa', P, 1)
+    Pa.point.set_vel(N, 10 * N.x)
+    raises(TypeError, lambda: linear_momentum(A, A, Pa))
+    raises(TypeError, lambda: linear_momentum(N, N, Pa))
+    assert linear_momentum(N, A, Pa) == 10 * N.x + 500 * N.y
+
+
+def test_angular_momentum_and_linear_momentum():
+    """A rod with length 2l, centroidal inertia I, and mass M along with a
+    particle of mass m fixed to the end of the rod rotate with an angular rate
+    of omega about point O which is fixed to the non-particle end of the rod.
+    The rod's reference frame is A and the inertial frame is N."""
+    m, M, l, I = symbols('m, M, l, I')
+    omega = dynamicsymbols('omega')
+    N = ReferenceFrame('N')
+    a = ReferenceFrame('a')
+    O = Point('O')
+    Ac = O.locatenew('Ac', l * N.x)
+    P = Ac.locatenew('P', l * N.x)
+    O.set_vel(N, 0 * N.x)
+    a.set_ang_vel(N, omega * N.z)
+    Ac.v2pt_theory(O, N, a)
+    P.v2pt_theory(O, N, a)
+    Pa = Particle('Pa', P, m)
+    A = RigidBody('A', Ac, a, M, (I * outer(N.z, N.z), Ac))
+    expected = 2 * m * omega * l * N.y + M * l * omega * N.y
+    assert linear_momentum(N, A, Pa) == expected
+    raises(TypeError, lambda: angular_momentum(N, N, A, Pa))
+    raises(TypeError, lambda: angular_momentum(O, O, A, Pa))
+    raises(TypeError, lambda: angular_momentum(O, N, O, Pa))
+    expected = (I + M * l**2 + 4 * m * l**2) * omega * N.z
+    assert angular_momentum(O, N, A, Pa) == expected
+
+
+def test_kinetic_energy():
+    m, M, l1 = symbols('m M l1')
+    omega = dynamicsymbols('omega')
+    N = ReferenceFrame('N')
+    O = Point('O')
+    O.set_vel(N, 0 * N.x)
+    Ac = O.locatenew('Ac', l1 * N.x)
+    P = Ac.locatenew('P', l1 * N.x)
+    a = ReferenceFrame('a')
+    a.set_ang_vel(N, omega * N.z)
+    Ac.v2pt_theory(O, N, a)
+    P.v2pt_theory(O, N, a)
+    Pa = Particle('Pa', P, m)
+    I = outer(N.z, N.z)
+    A = RigidBody('A', Ac, a, M, (I, Ac))
+    raises(TypeError, lambda: kinetic_energy(Pa, Pa, A))
+    raises(TypeError, lambda: kinetic_energy(N, N, A))
+    assert 0 == (kinetic_energy(N, Pa, A) - (M*l1**2*omega**2/2
+            + 2*l1**2*m*omega**2 + omega**2/2)).expand()
+
+
+def test_potential_energy():
+    m, M, l1, g, h, H = symbols('m M l1 g h H')
+    omega = dynamicsymbols('omega')
+    N = ReferenceFrame('N')
+    O = Point('O')
+    O.set_vel(N, 0 * N.x)
+    Ac = O.locatenew('Ac', l1 * N.x)
+    P = Ac.locatenew('P', l1 * N.x)
+    a = ReferenceFrame('a')
+    a.set_ang_vel(N, omega * N.z)
+    Ac.v2pt_theory(O, N, a)
+    P.v2pt_theory(O, N, a)
+    Pa = Particle('Pa', P, m)
+    I = outer(N.z, N.z)
+    A = RigidBody('A', Ac, a, M, (I, Ac))
+    Pa.potential_energy = m * g * h
+    A.potential_energy = M * g * H
+    assert potential_energy(A, Pa) == m * g * h + M * g * H
+
+
+def test_Lagrangian():
+    M, m, g, h = symbols('M m g h')
+    N = ReferenceFrame('N')
+    O = Point('O')
+    O.set_vel(N, 0 * N.x)
+    P = O.locatenew('P', 1 * N.x)
+    P.set_vel(N, 10 * N.x)
+    Pa = Particle('Pa', P, 1)
+    Ac = O.locatenew('Ac', 2 * N.y)
+    Ac.set_vel(N, 5 * N.y)
+    a = ReferenceFrame('a')
+    a.set_ang_vel(N, 10 * N.z)
+    I = outer(N.z, N.z)
+    A = RigidBody('A', Ac, a, 20, (I, Ac))
+    Pa.potential_energy = m * g * h
+    A.potential_energy = M * g * h
+    raises(TypeError, lambda: Lagrangian(A, A, Pa))
+    raises(TypeError, lambda: Lagrangian(N, N, Pa))
+
+
+def test_msubs():
+    a, b = symbols('a, b')
+    x, y, z = dynamicsymbols('x, y, z')
+    # Test simple substitution
+    expr = Matrix([[a*x + b, x*y.diff() + y],
+                   [x.diff().diff(), z + sin(z.diff())]])
+    sol = Matrix([[a + b, y],
+                  [x.diff().diff(), 1]])
+    sd = {x: 1, z: 1, z.diff(): 0, y.diff(): 0}
+    assert msubs(expr, sd) == sol
+    # Test smart substitution
+    expr = cos(x + y)*tan(x + y) + b*x.diff()
+    sd = {x: 0, y: pi/2, x.diff(): 1}
+    assert msubs(expr, sd, smart=True) == b + 1
+    N = ReferenceFrame('N')
+    v = x*N.x + y*N.y
+    d = x*(N.x|N.x) + y*(N.y|N.y)
+    v_sol = 1*N.y
+    d_sol = 1*(N.y|N.y)
+    sd = {x: 0, y: 1}
+    assert msubs(v, sd) == v_sol
+    assert msubs(d, sd) == d_sol
+
+
+def test_find_dynamicsymbols():
+    a, b = symbols('a, b')
+    x, y, z = dynamicsymbols('x, y, z')
+    expr = Matrix([[a*x + b, x*y.diff() + y],
+                   [x.diff().diff(), z + sin(z.diff())]])
+    # Test finding all dynamicsymbols
+    sol = {x, y.diff(), y, x.diff().diff(), z, z.diff()}
+    assert find_dynamicsymbols(expr) == sol
+    # Test finding all but those in sym_list
+    exclude_list = [x, y, z]
+    sol = {y.diff(), x.diff().diff(), z.diff()}
+    assert find_dynamicsymbols(expr, exclude=exclude_list) == sol
+    # Test finding all dynamicsymbols in a vector with a given reference frame
+    d, e, f = dynamicsymbols('d, e, f')
+    A = ReferenceFrame('A')
+    v = d * A.x + e * A.y + f * A.z
+    sol = {d, e, f}
+    assert find_dynamicsymbols(v, reference_frame=A) == sol
+    # Test if a ValueError is raised on supplying only a vector as input
+    raises(ValueError, lambda: find_dynamicsymbols(v))
+
+
+# This function tests the center_of_mass() function
+# that was added in PR #14758 to compute the center of
+# mass of a system of bodies.
+def test_center_of_mass():
+    a = ReferenceFrame('a')
+    m = symbols('m', real=True)
+    p1 = Particle('p1', Point('p1_pt'), S.One)
+    p2 = Particle('p2', Point('p2_pt'), S(2))
+    p3 = Particle('p3', Point('p3_pt'), S(3))
+    p4 = Particle('p4', Point('p4_pt'), m)
+    b_f = ReferenceFrame('b_f')
+    b_cm = Point('b_cm')
+    mb = symbols('mb')
+    b = RigidBody('b', b_cm, b_f, mb, (outer(b_f.x, b_f.x), b_cm))
+    p2.point.set_pos(p1.point, a.x)
+    p3.point.set_pos(p1.point, a.x + a.y)
+    p4.point.set_pos(p1.point, a.y)
+    b.masscenter.set_pos(p1.point, a.y + a.z)
+    point_o=Point('o')
+    point_o.set_pos(p1.point, center_of_mass(p1.point, p1, p2, p3, p4, b))
+    expr = 5/(m + mb + 6)*a.x + (m + mb + 3)/(m + mb + 6)*a.y + mb/(m + mb + 6)*a.z
+    assert point_o.pos_from(p1.point)-expr == 0
+
+
+def test_validate_coordinates():
+    q1, q2, q3, u1, u2, u3, ua1, ua2, ua3 = dynamicsymbols('q1:4 u1:4 ua1:4')
+    s1, s2, s3 = symbols('s1:4')
+    # Test normal
+    _validate_coordinates([q1, q2, q3], [u1, u2, u3],
+                          u_auxiliary=[ua1, ua2, ua3])
+    # Test not equal number of coordinates and speeds
+    _validate_coordinates([q1, q2])
+    _validate_coordinates([q1, q2], [u1])
+    _validate_coordinates(speeds=[u1, u2])
+    # Test duplicate
+    _validate_coordinates([q1, q2, q2], [u1, u2, u3], check_duplicates=False)
+    raises(ValueError, lambda: _validate_coordinates(
+        [q1, q2, q2], [u1, u2, u3]))
+    _validate_coordinates([q1, q2, q3], [u1, u2, u2], check_duplicates=False)
+    raises(ValueError, lambda: _validate_coordinates(
+        [q1, q2, q3], [u1, u2, u2], check_duplicates=True))
+    raises(ValueError, lambda: _validate_coordinates(
+        [q1, q2, q3], [q1, u2, u3], check_duplicates=True))
+    _validate_coordinates([q1, q2, q3], [u1, u2, u3], check_duplicates=False,
+                          u_auxiliary=[u1, ua2, ua2])
+    raises(ValueError, lambda: _validate_coordinates(
+        [q1, q2, q3], [u1, u2, u3], u_auxiliary=[u1, ua2, ua3]))
+    raises(ValueError, lambda: _validate_coordinates(
+        [q1, q2, q3], [u1, u2, u3], u_auxiliary=[q1, ua2, ua3]))
+    raises(ValueError, lambda: _validate_coordinates(
+        [q1, q2, q3], [u1, u2, u3], u_auxiliary=[ua1, ua2, ua2]))
+    # Test is_dynamicsymbols
+    _validate_coordinates([q1 + q2, q3], is_dynamicsymbols=False)
+    raises(ValueError, lambda: _validate_coordinates([q1 + q2, q3]))
+    _validate_coordinates([s1, q1, q2], [0, u1, u2], is_dynamicsymbols=False)
+    raises(ValueError, lambda: _validate_coordinates(
+        [s1, q1, q2], [0, u1, u2], is_dynamicsymbols=True))
+    _validate_coordinates([s1 + s2 + s3, q1], [0, u1], is_dynamicsymbols=False)
+    raises(ValueError, lambda: _validate_coordinates(
+        [s1 + s2 + s3, q1], [0, u1], is_dynamicsymbols=True))
+    _validate_coordinates(u_auxiliary=[s1, ua1], is_dynamicsymbols=False)
+    raises(ValueError, lambda: _validate_coordinates(u_auxiliary=[s1, ua1]))
+    # Test normal function
+    t = dynamicsymbols._t
+    a = symbols('a')
+    f1, f2 = symbols('f1:3', cls=Function)
+    _validate_coordinates([f1(a), f2(a)], is_dynamicsymbols=False)
+    raises(ValueError, lambda: _validate_coordinates([f1(a), f2(a)]))
+    raises(ValueError, lambda: _validate_coordinates(speeds=[f1(a), f2(a)]))
+    dynamicsymbols._t = a
+    _validate_coordinates([f1(a), f2(a)])
+    raises(ValueError, lambda: _validate_coordinates([f1(t), f2(t)]))
+    dynamicsymbols._t = t
+
+
+def test_parse_linear_solver():
+    A, b = Matrix(3, 3, symbols('a:9')), Matrix(3, 2, symbols('b:6'))
+    assert _parse_linear_solver(Matrix.LUsolve) == Matrix.LUsolve  # Test callable
+    assert _parse_linear_solver('LU')(A, b) == Matrix.LUsolve(A, b)
+
+
+def test_deprecated_moved_functions():
+    from sympy.physics.mechanics.functions import (
+        inertia, inertia_of_point_mass, gravity)
+    N = ReferenceFrame('N')
+    with warns_deprecated_sympy():
+        assert inertia(N, 0, 1, 0, 1) == (N.x | N.y) + (N.y | N.x) + (N.y | N.y)
+    with warns_deprecated_sympy():
+        assert inertia_of_point_mass(1, N.x + N.y, N) == (
+            (N.x | N.x) + (N.y | N.y) + 2 * (N.z | N.z) -
+            (N.x | N.y) - (N.y | N.x))
+    p = Particle('P')
+    with warns_deprecated_sympy():
+        assert gravity(-2 * N.z, p) == [(p.masscenter, -2 * p.mass * N.z)]

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_kane.py

@@ -0,0 +1,553 @@
+from sympy import solve
+from sympy import (cos, expand, Matrix, sin, symbols, tan, sqrt, S,
+                                zeros, eye)
+from sympy.simplify.simplify import simplify
+from sympy.physics.mechanics import (dynamicsymbols, ReferenceFrame, Point,
+                                     RigidBody, KanesMethod, inertia, Particle,
+                                     dot, find_dynamicsymbols)
+from sympy.testing.pytest import raises
+
+
+def test_invalid_coordinates():
+    # Simple pendulum, but use symbols instead of dynamicsymbols
+    l, m, g = symbols('l m g')
+    q, u = symbols('q u')  # Generalized coordinate
+    kd = [q.diff(dynamicsymbols._t) - u]
+    N, O = ReferenceFrame('N'), Point('O')
+    O.set_vel(N, 0)
+    P = Particle('P', Point('P'), m)
+    P.point.set_pos(O, l * (sin(q) * N.x - cos(q) * N.y))
+    F = (P.point, -m * g * N.y)
+    raises(ValueError, lambda: KanesMethod(N, [q], [u], kd, bodies=[P],
+                                           forcelist=[F]))
+
+
+def test_one_dof():
+    # This is for a 1 dof spring-mass-damper case.
+    # It is described in more detail in the KanesMethod docstring.
+    q, u = dynamicsymbols('q u')
+    qd, ud = dynamicsymbols('q u', 1)
+    m, c, k = symbols('m c k')
+    N = ReferenceFrame('N')
+    P = Point('P')
+    P.set_vel(N, u * N.x)
+
+    kd = [qd - u]
+    FL = [(P, (-k * q - c * u) * N.x)]
+    pa = Particle('pa', P, m)
+    BL = [pa]
+
+    KM = KanesMethod(N, [q], [u], kd)
+    KM.kanes_equations(BL, FL)
+
+    assert KM.bodies == BL
+    assert KM.loads == FL
+
+    MM = KM.mass_matrix
+    forcing = KM.forcing
+    rhs = MM.inv() * forcing
+    assert expand(rhs[0]) == expand(-(q * k + u * c) / m)
+
+    assert simplify(KM.rhs() -
+                    KM.mass_matrix_full.LUsolve(KM.forcing_full)) == zeros(2, 1)
+
+    assert (KM.linearize(A_and_B=True, )[0] == Matrix([[0, 1], [-k/m, -c/m]]))
+
+
+def test_two_dof():
+    # This is for a 2 d.o.f., 2 particle spring-mass-damper.
+    # The first coordinate is the displacement of the first particle, and the
+    # second is the relative displacement between the first and second
+    # particles. Speeds are defined as the time derivatives of the particles.
+    q1, q2, u1, u2 = dynamicsymbols('q1 q2 u1 u2')
+    q1d, q2d, u1d, u2d = dynamicsymbols('q1 q2 u1 u2', 1)
+    m, c1, c2, k1, k2 = symbols('m c1 c2 k1 k2')
+    N = ReferenceFrame('N')
+    P1 = Point('P1')
+    P2 = Point('P2')
+    P1.set_vel(N, u1 * N.x)
+    P2.set_vel(N, (u1 + u2) * N.x)
+    # Note we multiply the kinematic equation by an arbitrary factor
+    # to test the implicit vs explicit kinematics attribute
+    kd = [q1d/2 - u1/2, 2*q2d - 2*u2]
+
+    # Now we create the list of forces, then assign properties to each
+    # particle, then create a list of all particles.
+    FL = [(P1, (-k1 * q1 - c1 * u1 + k2 * q2 + c2 * u2) * N.x), (P2, (-k2 *
+        q2 - c2 * u2) * N.x)]
+    pa1 = Particle('pa1', P1, m)
+    pa2 = Particle('pa2', P2, m)
+    BL = [pa1, pa2]
+
+    # Finally we create the KanesMethod object, specify the inertial frame,
+    # pass relevant information, and form Fr & Fr*. Then we calculate the mass
+    # matrix and forcing terms, and finally solve for the udots.
+    KM = KanesMethod(N, q_ind=[q1, q2], u_ind=[u1, u2], kd_eqs=kd)
+    KM.kanes_equations(BL, FL)
+    MM = KM.mass_matrix
+    forcing = KM.forcing
+    rhs = MM.inv() * forcing
+    assert expand(rhs[0]) == expand((-k1 * q1 - c1 * u1 + k2 * q2 + c2 * u2)/m)
+    assert expand(rhs[1]) == expand((k1 * q1 + c1 * u1 - 2 * k2 * q2 - 2 *
+                                    c2 * u2) / m)
+
+    # Check that the explicit form is the default and kinematic mass matrix is identity
+    assert KM.explicit_kinematics
+    assert KM.mass_matrix_kin == eye(2)
+
+    # Check that for the implicit form the mass matrix is not identity
+    KM.explicit_kinematics = False
+    assert KM.mass_matrix_kin == Matrix([[S(1)/2, 0], [0, 2]])
+
+    # Check that whether using implicit or explicit kinematics the RHS
+    # equations are consistent with the matrix form
+    for explicit_kinematics in [False, True]:
+        KM.explicit_kinematics = explicit_kinematics
+        assert simplify(KM.rhs() -
+                        KM.mass_matrix_full.LUsolve(KM.forcing_full)) == zeros(4, 1)
+
+    # Make sure an error is raised if nonlinear kinematic differential
+    # equations are supplied.
+    kd = [q1d - u1**2, sin(q2d) - cos(u2)]
+    raises(ValueError, lambda: KanesMethod(N, q_ind=[q1, q2],
+                                           u_ind=[u1, u2], kd_eqs=kd))
+
+def test_pend():
+    q, u = dynamicsymbols('q u')
+    qd, ud = dynamicsymbols('q u', 1)
+    m, l, g = symbols('m l g')
+    N = ReferenceFrame('N')
+    P = Point('P')
+    P.set_vel(N, -l * u * sin(q) * N.x + l * u * cos(q) * N.y)
+    kd = [qd - u]
+
+    FL = [(P, m * g * N.x)]
+    pa = Particle('pa', P, m)
+    BL = [pa]
+
+    KM = KanesMethod(N, [q], [u], kd)
+    KM.kanes_equations(BL, FL)
+    MM = KM.mass_matrix
+    forcing = KM.forcing
+    rhs = MM.inv() * forcing
+    rhs.simplify()
+    assert expand(rhs[0]) == expand(-g / l * sin(q))
+    assert simplify(KM.rhs() -
+                    KM.mass_matrix_full.LUsolve(KM.forcing_full)) == zeros(2, 1)
+
+
+def test_rolling_disc():
+    # Rolling Disc Example
+    # Here the rolling disc is formed from the contact point up, removing the
+    # need to introduce generalized speeds. Only 3 configuration and three
+    # speed variables are need to describe this system, along with the disc's
+    # mass and radius, and the local gravity (note that mass will drop out).
+    q1, q2, q3, u1, u2, u3 = dynamicsymbols('q1 q2 q3 u1 u2 u3')
+    q1d, q2d, q3d, u1d, u2d, u3d = dynamicsymbols('q1 q2 q3 u1 u2 u3', 1)
+    r, m, g = symbols('r m g')
+
+    # The kinematics are formed by a series of simple rotations. Each simple
+    # rotation creates a new frame, and the next rotation is defined by the new
+    # frame's basis vectors. This example uses a 3-1-2 series of rotations, or
+    # Z, X, Y series of rotations. Angular velocity for this is defined using
+    # the second frame's basis (the lean frame).
+    N = ReferenceFrame('N')
+    Y = N.orientnew('Y', 'Axis', [q1, N.z])
+    L = Y.orientnew('L', 'Axis', [q2, Y.x])
+    R = L.orientnew('R', 'Axis', [q3, L.y])
+    w_R_N_qd = R.ang_vel_in(N)
+    R.set_ang_vel(N, u1 * L.x + u2 * L.y + u3 * L.z)
+
+    # This is the translational kinematics. We create a point with no velocity
+    # in N; this is the contact point between the disc and ground. Next we form
+    # the position vector from the contact point to the disc's center of mass.
+    # Finally we form the velocity and acceleration of the disc.
+    C = Point('C')
+    C.set_vel(N, 0)
+    Dmc = C.locatenew('Dmc', r * L.z)
+    Dmc.v2pt_theory(C, N, R)
+
+    # This is a simple way to form the inertia dyadic.
+    I = inertia(L, m / 4 * r**2, m / 2 * r**2, m / 4 * r**2)
+
+    # Kinematic differential equations; how the generalized coordinate time
+    # derivatives relate to generalized speeds.
+    kd = [dot(R.ang_vel_in(N) - w_R_N_qd, uv) for uv in L]
+
+    # Creation of the force list; it is the gravitational force at the mass
+    # center of the disc. Then we create the disc by assigning a Point to the
+    # center of mass attribute, a ReferenceFrame to the frame attribute, and mass
+    # and inertia. Then we form the body list.
+    ForceList = [(Dmc, - m * g * Y.z)]
+    BodyD = RigidBody('BodyD', Dmc, R, m, (I, Dmc))
+    BodyList = [BodyD]
+
+    # Finally we form the equations of motion, using the same steps we did
+    # before. Specify inertial frame, supply generalized speeds, supply
+    # kinematic differential equation dictionary, compute Fr from the force
+    # list and Fr* from the body list, compute the mass matrix and forcing
+    # terms, then solve for the u dots (time derivatives of the generalized
+    # speeds).
+    KM = KanesMethod(N, q_ind=[q1, q2, q3], u_ind=[u1, u2, u3], kd_eqs=kd)
+    KM.kanes_equations(BodyList, ForceList)
+    MM = KM.mass_matrix
+    forcing = KM.forcing
+    rhs = MM.inv() * forcing
+    kdd = KM.kindiffdict()
+    rhs = rhs.subs(kdd)
+    rhs.simplify()
+    assert rhs.expand() == Matrix([(6*u2*u3*r - u3**2*r*tan(q2) +
+        4*g*sin(q2))/(5*r), -2*u1*u3/3, u1*(-2*u2 + u3*tan(q2))]).expand()
+    assert simplify(KM.rhs() -
+                    KM.mass_matrix_full.LUsolve(KM.forcing_full)) == zeros(6, 1)
+
+    # This code tests our output vs. benchmark values. When r=g=m=1, the
+    # critical speed (where all eigenvalues of the linearized equations are 0)
+    # is 1 / sqrt(3) for the upright case.
+    A = KM.linearize(A_and_B=True)[0]
+    A_upright = A.subs({r: 1, g: 1, m: 1}).subs({q1: 0, q2: 0, q3: 0, u1: 0, u3: 0})
+    import sympy
+    assert sympy.sympify(A_upright.subs({u2: 1 / sqrt(3)})).eigenvals() == {S.Zero: 6}
+
+
+def test_aux():
+    # Same as above, except we have 2 auxiliary speeds for the ground contact
+    # point, which is known to be zero. In one case, we go through then
+    # substitute the aux. speeds in at the end (they are zero, as well as their
+    # derivative), in the other case, we use the built-in auxiliary speed part
+    # of KanesMethod. The equations from each should be the same.
+    q1, q2, q3, u1, u2, u3 = dynamicsymbols('q1 q2 q3 u1 u2 u3')
+    q1d, q2d, q3d, u1d, u2d, u3d = dynamicsymbols('q1 q2 q3 u1 u2 u3', 1)
+    u4, u5, f1, f2 = dynamicsymbols('u4, u5, f1, f2')
+    u4d, u5d = dynamicsymbols('u4, u5', 1)
+    r, m, g = symbols('r m g')
+
+    N = ReferenceFrame('N')
+    Y = N.orientnew('Y', 'Axis', [q1, N.z])
+    L = Y.orientnew('L', 'Axis', [q2, Y.x])
+    R = L.orientnew('R', 'Axis', [q3, L.y])
+    w_R_N_qd = R.ang_vel_in(N)
+    R.set_ang_vel(N, u1 * L.x + u2 * L.y + u3 * L.z)
+
+    C = Point('C')
+    C.set_vel(N, u4 * L.x + u5 * (Y.z ^ L.x))
+    Dmc = C.locatenew('Dmc', r * L.z)
+    Dmc.v2pt_theory(C, N, R)
+    Dmc.a2pt_theory(C, N, R)
+
+    I = inertia(L, m / 4 * r**2, m / 2 * r**2, m / 4 * r**2)
+
+    kd = [dot(R.ang_vel_in(N) - w_R_N_qd, uv) for uv in L]
+
+    ForceList = [(Dmc, - m * g * Y.z), (C, f1 * L.x + f2 * (Y.z ^ L.x))]
+    BodyD = RigidBody('BodyD', Dmc, R, m, (I, Dmc))
+    BodyList = [BodyD]
+
+    KM = KanesMethod(N, q_ind=[q1, q2, q3], u_ind=[u1, u2, u3, u4, u5],
+                     kd_eqs=kd)
+    (fr, frstar) = KM.kanes_equations(BodyList, ForceList)
+    fr = fr.subs({u4d: 0, u5d: 0}).subs({u4: 0, u5: 0})
+    frstar = frstar.subs({u4d: 0, u5d: 0}).subs({u4: 0, u5: 0})
+
+    KM2 = KanesMethod(N, q_ind=[q1, q2, q3], u_ind=[u1, u2, u3], kd_eqs=kd,
+                      u_auxiliary=[u4, u5])
+    (fr2, frstar2) = KM2.kanes_equations(BodyList, ForceList)
+    fr2 = fr2.subs({u4d: 0, u5d: 0}).subs({u4: 0, u5: 0})
+    frstar2 = frstar2.subs({u4d: 0, u5d: 0}).subs({u4: 0, u5: 0})
+
+    frstar.simplify()
+    frstar2.simplify()
+
+    assert (fr - fr2).expand() == Matrix([0, 0, 0, 0, 0])
+    assert (frstar - frstar2).expand() == Matrix([0, 0, 0, 0, 0])
+
+
+def test_parallel_axis():
+    # This is for a 2 dof inverted pendulum on a cart.
+    # This tests the parallel axis code in KanesMethod. The inertia of the
+    # pendulum is defined about the hinge, not about the center of mass.
+
+    # Defining the constants and knowns of the system
+    gravity = symbols('g')
+    k, ls = symbols('k ls')
+    a, mA, mC = symbols('a mA mC')
+    F = dynamicsymbols('F')
+    Ix, Iy, Iz = symbols('Ix Iy Iz')
+
+    # Declaring the Generalized coordinates and speeds
+    q1, q2 = dynamicsymbols('q1 q2')
+    q1d, q2d = dynamicsymbols('q1 q2', 1)
+    u1, u2 = dynamicsymbols('u1 u2')
+    u1d, u2d = dynamicsymbols('u1 u2', 1)
+
+    # Creating reference frames
+    N = ReferenceFrame('N')
+    A = ReferenceFrame('A')
+
+    A.orient(N, 'Axis', [-q2, N.z])
+    A.set_ang_vel(N, -u2 * N.z)
+
+    # Origin of Newtonian reference frame
+    O = Point('O')
+
+    # Creating and Locating the positions of the cart, C, and the
+    # center of mass of the pendulum, A
+    C = O.locatenew('C', q1 * N.x)
+    Ao = C.locatenew('Ao', a * A.y)
+
+    # Defining velocities of the points
+    O.set_vel(N, 0)
+    C.set_vel(N, u1 * N.x)
+    Ao.v2pt_theory(C, N, A)
+    Cart = Particle('Cart', C, mC)
+    Pendulum = RigidBody('Pendulum', Ao, A, mA, (inertia(A, Ix, Iy, Iz), C))
+
+    # kinematical differential equations
+
+    kindiffs = [q1d - u1, q2d - u2]
+
+    bodyList = [Cart, Pendulum]
+
+    forceList = [(Ao, -N.y * gravity * mA),
+                 (C, -N.y * gravity * mC),
+                 (C, -N.x * k * (q1 - ls)),
+                 (C, N.x * F)]
+
+    km = KanesMethod(N, [q1, q2], [u1, u2], kindiffs)
+    (fr, frstar) = km.kanes_equations(bodyList, forceList)
+    mm = km.mass_matrix_full
+    assert mm[3, 3] == Iz
+
+def test_input_format():
+    # 1 dof problem from test_one_dof
+    q, u = dynamicsymbols('q u')
+    qd, ud = dynamicsymbols('q u', 1)
+    m, c, k = symbols('m c k')
+    N = ReferenceFrame('N')
+    P = Point('P')
+    P.set_vel(N, u * N.x)
+
+    kd = [qd - u]
+    FL = [(P, (-k * q - c * u) * N.x)]
+    pa = Particle('pa', P, m)
+    BL = [pa]
+
+    KM = KanesMethod(N, [q], [u], kd)
+    # test for input format kane.kanes_equations((body1, body2, particle1))
+    assert KM.kanes_equations(BL)[0] == Matrix([0])
+    # test for input format kane.kanes_equations(bodies=(body1, body 2), loads=(load1,load2))
+    assert KM.kanes_equations(bodies=BL, loads=None)[0] == Matrix([0])
+    # test for input format kane.kanes_equations(bodies=(body1, body 2), loads=None)
+    assert KM.kanes_equations(BL, loads=None)[0] == Matrix([0])
+    # test for input format kane.kanes_equations(bodies=(body1, body 2))
+    assert KM.kanes_equations(BL)[0] == Matrix([0])
+    # test for input format kane.kanes_equations(bodies=(body1, body2), loads=[])
+    assert KM.kanes_equations(BL, [])[0] == Matrix([0])
+    # test for error raised when a wrong force list (in this case a string) is provided
+    raises(ValueError, lambda: KM._form_fr('bad input'))
+
+    # 1 dof problem from test_one_dof with FL & BL in instance
+    KM = KanesMethod(N, [q], [u], kd, bodies=BL, forcelist=FL)
+    assert KM.kanes_equations()[0] == Matrix([-c*u - k*q])
+
+    # 2 dof problem from test_two_dof
+    q1, q2, u1, u2 = dynamicsymbols('q1 q2 u1 u2')
+    q1d, q2d, u1d, u2d = dynamicsymbols('q1 q2 u1 u2', 1)
+    m, c1, c2, k1, k2 = symbols('m c1 c2 k1 k2')
+    N = ReferenceFrame('N')
+    P1 = Point('P1')
+    P2 = Point('P2')
+    P1.set_vel(N, u1 * N.x)
+    P2.set_vel(N, (u1 + u2) * N.x)
+    kd = [q1d - u1, q2d - u2]
+
+    FL = ((P1, (-k1 * q1 - c1 * u1 + k2 * q2 + c2 * u2) * N.x), (P2, (-k2 *
+        q2 - c2 * u2) * N.x))
+    pa1 = Particle('pa1', P1, m)
+    pa2 = Particle('pa2', P2, m)
+    BL = (pa1, pa2)
+
+    KM = KanesMethod(N, q_ind=[q1, q2], u_ind=[u1, u2], kd_eqs=kd)
+    # test for input format
+    # kane.kanes_equations((body1, body2), (load1, load2))
+    KM.kanes_equations(BL, FL)
+    MM = KM.mass_matrix
+    forcing = KM.forcing
+    rhs = MM.inv() * forcing
+    assert expand(rhs[0]) == expand((-k1 * q1 - c1 * u1 + k2 * q2 + c2 * u2)/m)
+    assert expand(rhs[1]) == expand((k1 * q1 + c1 * u1 - 2 * k2 * q2 - 2 *
+                                    c2 * u2) / m)
+
+
+def test_implicit_kinematics():
+    # Test that implicit kinematics can handle complicated
+    # equations that explicit form struggles with
+    # See https://github.com/sympy/sympy/issues/22626
+
+    # Inertial frame
+    NED = ReferenceFrame('NED')
+    NED_o = Point('NED_o')
+    NED_o.set_vel(NED, 0)
+
+    # body frame
+    q_att = dynamicsymbols('lambda_0:4', real=True)
+    B = NED.orientnew('B', 'Quaternion', q_att)
+
+    # Generalized coordinates
+    q_pos = dynamicsymbols('B_x:z')
+    B_cm = NED_o.locatenew('B_cm', q_pos[0]*B.x + q_pos[1]*B.y + q_pos[2]*B.z)
+
+    q_ind = q_att[1:] + q_pos
+    q_dep = [q_att[0]]
+
+    kinematic_eqs = []
+
+    # Generalized velocities
+    B_ang_vel = B.ang_vel_in(NED)
+    P, Q, R = dynamicsymbols('P Q R')
+    B.set_ang_vel(NED, P*B.x + Q*B.y + R*B.z)
+
+    B_ang_vel_kd = (B.ang_vel_in(NED) - B_ang_vel).simplify()
+
+    # Equating the two gives us the kinematic equation
+    kinematic_eqs += [
+        B_ang_vel_kd & B.x,
+        B_ang_vel_kd & B.y,
+        B_ang_vel_kd & B.z
+    ]
+
+    B_cm_vel = B_cm.vel(NED)
+    U, V, W = dynamicsymbols('U V W')
+    B_cm.set_vel(NED, U*B.x + V*B.y + W*B.z)
+
+    # Compute the velocity of the point using the two methods
+    B_ref_vel_kd = (B_cm.vel(NED) - B_cm_vel)
+
+    # taking dot product with unit vectors to get kinematic equations
+    # relating body coordinates and velocities
+
+    # Note, there is a choice to dot with NED.xyz here. That makes
+    # the implicit form have some bigger terms but is still fine, the
+    # explicit form still struggles though
+    kinematic_eqs += [
+                      B_ref_vel_kd & B.x,
+                      B_ref_vel_kd & B.y,
+                      B_ref_vel_kd & B.z,
+                     ]
+
+    u_ind = [U, V, W, P, Q, R]
+
+    # constraints
+    q_att_vec = Matrix(q_att)
+    config_cons = [(q_att_vec.T*q_att_vec)[0] - 1] #unit norm
+    kinematic_eqs = kinematic_eqs + [(q_att_vec.T * q_att_vec.diff())[0]]
+
+    try:
+        KM = KanesMethod(NED, q_ind, u_ind,
+          q_dependent= q_dep,
+          kd_eqs = kinematic_eqs,
+          configuration_constraints = config_cons,
+          velocity_constraints= [],
+          u_dependent= [], #no dependent speeds
+          u_auxiliary = [], # No auxiliary speeds
+          explicit_kinematics = False # implicit kinematics
+        )
+    except Exception as e:
+        raise e
+
+    # mass and inertia dyadic relative to CM
+    M_B = symbols('M_B')
+    J_B = inertia(B, *[S(f'J_B_{ax}')*(1 if ax[0] == ax[1] else -1)
+            for ax in ['xx', 'yy', 'zz', 'xy', 'yz', 'xz']])
+    J_B = J_B.subs({S('J_B_xy'): 0, S('J_B_yz'): 0})
+    RB = RigidBody('RB', B_cm, B, M_B, (J_B, B_cm))
+
+    rigid_bodies = [RB]
+    # Forces
+    force_list = [
+        #gravity pointing down
+        (RB.masscenter, RB.mass*S('g')*NED.z),
+        #generic forces and torques in body frame(inputs)
+        (RB.frame, dynamicsymbols('T_z')*B.z),
+        (RB.masscenter, dynamicsymbols('F_z')*B.z)
+    ]
+
+    KM.kanes_equations(rigid_bodies, force_list)
+
+    # Expecting implicit form to be less than 5% of the flops
+    n_ops_implicit = sum(
+        [x.count_ops() for x in KM.forcing_full] +
+        [x.count_ops() for x in KM.mass_matrix_full]
+    )
+    # Save implicit kinematic matrices to use later
+    mass_matrix_kin_implicit = KM.mass_matrix_kin
+    forcing_kin_implicit = KM.forcing_kin
+
+    KM.explicit_kinematics = True
+    n_ops_explicit = sum(
+        [x.count_ops() for x in KM.forcing_full] +
+        [x.count_ops() for x in KM.mass_matrix_full]
+    )
+    forcing_kin_explicit = KM.forcing_kin
+
+    assert n_ops_implicit / n_ops_explicit < .05
+
+    # Ideally we would check that implicit and explicit equations give the same result as done in test_one_dof
+    # But the whole raison-d'etre of the implicit equations is to deal with problems such
+    # as this one where the explicit form is too complicated to handle, especially the angular part
+    # (i.e. tests would be too slow)
+    # Instead, we check that the kinematic equations are correct using more fundamental tests:
+    #
+    # (1) that we recover the kinematic equations we have provided
+    assert (mass_matrix_kin_implicit * KM.q.diff() - forcing_kin_implicit) == Matrix(kinematic_eqs)
+
+    # (2) that rate of quaternions matches what 'textbook' solutions give
+    # Note that we just use the explicit kinematics for the linear velocities
+    # as they are not as complicated as the angular ones
+    qdot_candidate = forcing_kin_explicit
+
+    quat_dot_textbook = Matrix([
+        [0, -P, -Q, -R],
+        [P,  0,  R, -Q],
+        [Q, -R,  0,  P],
+        [R,  Q, -P,  0],
+    ]) * q_att_vec / 2
+
+    # Again, if we don't use this "textbook" solution
+    # sympy will struggle to deal with the terms related to quaternion rates
+    # due to the number of operations involved
+    qdot_candidate[-1] = quat_dot_textbook[0] # lambda_0, note the [-1] as sympy's Kane puts the dependent coordinate last
+    qdot_candidate[0]  = quat_dot_textbook[1] # lambda_1
+    qdot_candidate[1]  = quat_dot_textbook[2] # lambda_2
+    qdot_candidate[2]  = quat_dot_textbook[3] # lambda_3
+
+    # sub the config constraint in the candidate solution and compare to the implicit rhs
+    lambda_0_sol = solve(config_cons[0], q_att_vec[0])[1]
+    lhs_candidate = simplify(mass_matrix_kin_implicit * qdot_candidate).subs({q_att_vec[0]: lambda_0_sol})
+    assert lhs_candidate == forcing_kin_implicit
+
+def test_issue_24887():
+    # Spherical pendulum
+    g, l, m, c = symbols('g l m c')
+    q1, q2, q3, u1, u2, u3 = dynamicsymbols('q1:4 u1:4')
+    N = ReferenceFrame('N')
+    A = ReferenceFrame('A')
+    A.orient_body_fixed(N, (q1, q2, q3), 'zxy')
+    N_w_A = A.ang_vel_in(N)
+    # A.set_ang_vel(N, u1 * A.x + u2 * A.y + u3 * A.z)
+    kdes = [N_w_A.dot(A.x) - u1, N_w_A.dot(A.y) - u2, N_w_A.dot(A.z) - u3]
+    O = Point('O')
+    O.set_vel(N, 0)
+    Po = O.locatenew('Po', -l * A.y)
+    Po.set_vel(A, 0)
+    P = Particle('P', Po, m)
+    kane = KanesMethod(N, [q1, q2, q3], [u1, u2, u3], kdes, bodies=[P],
+                       forcelist=[(Po, -m * g * N.y)])
+    kane.kanes_equations()
+    expected_md = m * l ** 2 * Matrix([[1, 0, 0], [0, 0, 0], [0, 0, 1]])
+    expected_fd = Matrix([
+        [l*m*(g*(sin(q1)*sin(q3) - sin(q2)*cos(q1)*cos(q3)) - l*u2*u3)],
+        [0], [l*m*(-g*(sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1)) + l*u1*u2)]])
+    assert find_dynamicsymbols(kane.forcing).issubset({q1, q2, q3, u1, u2, u3})
+    assert simplify(kane.mass_matrix - expected_md) == zeros(3, 3)
+    assert simplify(kane.forcing - expected_fd) == zeros(3, 1)

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_lagrange2.py

@@ -0,0 +1,46 @@
+from sympy import symbols
+from sympy.physics.mechanics import dynamicsymbols
+from sympy.physics.mechanics import ReferenceFrame, Point, Particle
+from sympy.physics.mechanics import LagrangesMethod, Lagrangian
+
+### This test asserts that a system with more than one external forces
+### is acurately formed with Lagrange method (see issue #8626)
+
+def test_lagrange_2forces():
+    ### Equations for two damped springs in serie with two forces
+
+    ### generalized coordinates
+    q1, q2 = dynamicsymbols('q1, q2')
+    ### generalized speeds
+    q1d, q2d = dynamicsymbols('q1, q2', 1)
+
+    ### Mass, spring strength, friction coefficient
+    m, k, nu = symbols('m, k, nu')
+
+    N = ReferenceFrame('N')
+    O = Point('O')
+
+    ### Two points
+    P1 = O.locatenew('P1', q1 * N.x)
+    P1.set_vel(N, q1d * N.x)
+    P2 = O.locatenew('P1', q2 * N.x)
+    P2.set_vel(N, q2d * N.x)
+
+    pP1 = Particle('pP1', P1, m)
+    pP1.potential_energy = k * q1**2 / 2
+
+    pP2 = Particle('pP2', P2, m)
+    pP2.potential_energy = k * (q1 - q2)**2 / 2
+
+    #### Friction forces
+    forcelist = [(P1, - nu * q1d * N.x),
+                 (P2, - nu * q2d * N.x)]
+    lag = Lagrangian(N, pP1, pP2)
+
+    l_method = LagrangesMethod(lag, (q1, q2), forcelist=forcelist, frame=N)
+    l_method.form_lagranges_equations()
+
+    eq1 = l_method.eom[0]
+    assert eq1.diff(q1d) == nu
+    eq2 = l_method.eom[1]
+    assert eq2.diff(q2d) == nu

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_method.py

@@ -0,0 +1,5 @@
+from sympy.physics.mechanics.method import _Methods
+from sympy.testing.pytest import raises
+
+def test_method():
+    raises(TypeError, lambda: _Methods())

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_models.py

@@ -0,0 +1,117 @@
+import sympy.physics.mechanics.models as models
+from sympy import (cos, sin, Matrix, symbols, zeros)
+from sympy.simplify.simplify import simplify
+from sympy.physics.mechanics import (dynamicsymbols)
+
+
+def test_multi_mass_spring_damper_inputs():
+
+    c0, k0, m0 = symbols("c0 k0 m0")
+    g = symbols("g")
+    v0, x0, f0 = dynamicsymbols("v0 x0 f0")
+
+    kane1 = models.multi_mass_spring_damper(1)
+    massmatrix1 = Matrix([[m0]])
+    forcing1 = Matrix([[-c0*v0 - k0*x0]])
+    assert simplify(massmatrix1 - kane1.mass_matrix) == Matrix([0])
+    assert simplify(forcing1 - kane1.forcing) == Matrix([0])
+
+    kane2 = models.multi_mass_spring_damper(1, True)
+    massmatrix2 = Matrix([[m0]])
+    forcing2 = Matrix([[-c0*v0 + g*m0 - k0*x0]])
+    assert simplify(massmatrix2 - kane2.mass_matrix) == Matrix([0])
+    assert simplify(forcing2 - kane2.forcing) == Matrix([0])
+
+    kane3 = models.multi_mass_spring_damper(1, True, True)
+    massmatrix3 = Matrix([[m0]])
+    forcing3 = Matrix([[-c0*v0 + g*m0 - k0*x0 + f0]])
+    assert simplify(massmatrix3 - kane3.mass_matrix) == Matrix([0])
+    assert simplify(forcing3 - kane3.forcing) == Matrix([0])
+
+    kane4 = models.multi_mass_spring_damper(1, False, True)
+    massmatrix4 = Matrix([[m0]])
+    forcing4 = Matrix([[-c0*v0 - k0*x0 + f0]])
+    assert simplify(massmatrix4 - kane4.mass_matrix) == Matrix([0])
+    assert simplify(forcing4 - kane4.forcing) == Matrix([0])
+
+
+def test_multi_mass_spring_damper_higher_order():
+    c0, k0, m0 = symbols("c0 k0 m0")
+    c1, k1, m1 = symbols("c1 k1 m1")
+    c2, k2, m2 = symbols("c2 k2 m2")
+    v0, x0 = dynamicsymbols("v0 x0")
+    v1, x1 = dynamicsymbols("v1 x1")
+    v2, x2 = dynamicsymbols("v2 x2")
+
+    kane1 = models.multi_mass_spring_damper(3)
+    massmatrix1 = Matrix([[m0 + m1 + m2, m1 + m2, m2],
+                          [m1 + m2, m1 + m2, m2],
+                          [m2, m2, m2]])
+    forcing1 = Matrix([[-c0*v0 - k0*x0],
+                       [-c1*v1 - k1*x1],
+                       [-c2*v2 - k2*x2]])
+    assert simplify(massmatrix1 - kane1.mass_matrix) == zeros(3)
+    assert simplify(forcing1 - kane1.forcing) == Matrix([0, 0, 0])
+
+
+def test_n_link_pendulum_on_cart_inputs():
+    l0, m0 = symbols("l0 m0")
+    m1 = symbols("m1")
+    g = symbols("g")
+    q0, q1, F, T1 = dynamicsymbols("q0 q1 F T1")
+    u0, u1 = dynamicsymbols("u0 u1")
+
+    kane1 = models.n_link_pendulum_on_cart(1)
+    massmatrix1 = Matrix([[m0 + m1, -l0*m1*cos(q1)],
+                          [-l0*m1*cos(q1), l0**2*m1]])
+    forcing1 = Matrix([[-l0*m1*u1**2*sin(q1) + F], [g*l0*m1*sin(q1)]])
+    assert simplify(massmatrix1 - kane1.mass_matrix) == zeros(2)
+    assert simplify(forcing1 - kane1.forcing) == Matrix([0, 0])
+
+    kane2 = models.n_link_pendulum_on_cart(1, False)
+    massmatrix2 = Matrix([[m0 + m1, -l0*m1*cos(q1)],
+                          [-l0*m1*cos(q1), l0**2*m1]])
+    forcing2 = Matrix([[-l0*m1*u1**2*sin(q1)], [g*l0*m1*sin(q1)]])
+    assert simplify(massmatrix2 - kane2.mass_matrix) == zeros(2)
+    assert simplify(forcing2 - kane2.forcing) == Matrix([0, 0])
+
+    kane3 = models.n_link_pendulum_on_cart(1, False, True)
+    massmatrix3 = Matrix([[m0 + m1, -l0*m1*cos(q1)],
+                          [-l0*m1*cos(q1), l0**2*m1]])
+    forcing3 = Matrix([[-l0*m1*u1**2*sin(q1)], [g*l0*m1*sin(q1) + T1]])
+    assert simplify(massmatrix3 - kane3.mass_matrix) == zeros(2)
+    assert simplify(forcing3 - kane3.forcing) == Matrix([0, 0])
+
+    kane4 = models.n_link_pendulum_on_cart(1, True, False)
+    massmatrix4 = Matrix([[m0 + m1, -l0*m1*cos(q1)],
+                          [-l0*m1*cos(q1), l0**2*m1]])
+    forcing4 = Matrix([[-l0*m1*u1**2*sin(q1) + F], [g*l0*m1*sin(q1)]])
+    assert simplify(massmatrix4 - kane4.mass_matrix) == zeros(2)
+    assert simplify(forcing4 - kane4.forcing) == Matrix([0, 0])
+
+
+def test_n_link_pendulum_on_cart_higher_order():
+    l0, m0 = symbols("l0 m0")
+    l1, m1 = symbols("l1 m1")
+    m2 = symbols("m2")
+    g = symbols("g")
+    q0, q1, q2 = dynamicsymbols("q0 q1 q2")
+    u0, u1, u2 = dynamicsymbols("u0 u1 u2")
+    F, T1 = dynamicsymbols("F T1")
+
+    kane1 = models.n_link_pendulum_on_cart(2)
+    massmatrix1 = Matrix([[m0 + m1 + m2, -l0*m1*cos(q1) - l0*m2*cos(q1),
+                           -l1*m2*cos(q2)],
+                          [-l0*m1*cos(q1) - l0*m2*cos(q1), l0**2*m1 + l0**2*m2,
+                           l0*l1*m2*(sin(q1)*sin(q2) + cos(q1)*cos(q2))],
+                          [-l1*m2*cos(q2),
+                           l0*l1*m2*(sin(q1)*sin(q2) + cos(q1)*cos(q2)),
+                           l1**2*m2]])
+    forcing1 = Matrix([[-l0*m1*u1**2*sin(q1) - l0*m2*u1**2*sin(q1) -
+                        l1*m2*u2**2*sin(q2) + F],
+                       [g*l0*m1*sin(q1) + g*l0*m2*sin(q1) -
+                        l0*l1*m2*(sin(q1)*cos(q2) - sin(q2)*cos(q1))*u2**2],
+                       [g*l1*m2*sin(q2) - l0*l1*m2*(-sin(q1)*cos(q2) +
+                                                    sin(q2)*cos(q1))*u1**2]])
+    assert simplify(massmatrix1 - kane1.mass_matrix) == zeros(3)
+    assert simplify(forcing1 - kane1.forcing) == Matrix([0, 0, 0])

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_particle.py

@@ -0,0 +1,78 @@
+from sympy import symbols
+from sympy.physics.mechanics import Point, Particle, ReferenceFrame, inertia
+from sympy.physics.mechanics.body_base import BodyBase
+from sympy.testing.pytest import raises, warns_deprecated_sympy
+
+
+def test_particle_default():
+    # Test default
+    p = Particle('P')
+    assert p.name == 'P'
+    assert p.mass == symbols('P_mass')
+    assert p.masscenter.name == 'P_masscenter'
+    assert p.potential_energy == 0
+    assert p.__str__() == 'P'
+    assert p.__repr__() == ("Particle('P', masscenter=P_masscenter, "
+                            "mass=P_mass)")
+    raises(AttributeError, lambda: p.frame)
+
+
+def test_particle():
+    # Test initializing with parameters
+    m, m2, v1, v2, v3, r, g, h = symbols('m m2 v1 v2 v3 r g h')
+    P = Point('P')
+    P2 = Point('P2')
+    p = Particle('pa', P, m)
+    assert isinstance(p, BodyBase)
+    assert p.mass == m
+    assert p.point == P
+    # Test the mass setter
+    p.mass = m2
+    assert p.mass == m2
+    # Test the point setter
+    p.point = P2
+    assert p.point == P2
+    # Test the linear momentum function
+    N = ReferenceFrame('N')
+    O = Point('O')
+    P2.set_pos(O, r * N.y)
+    P2.set_vel(N, v1 * N.x)
+    raises(TypeError, lambda: Particle(P, P, m))
+    raises(TypeError, lambda: Particle('pa', m, m))
+    assert p.linear_momentum(N) == m2 * v1 * N.x
+    assert p.angular_momentum(O, N) == -m2 * r * v1 * N.z
+    P2.set_vel(N, v2 * N.y)
+    assert p.linear_momentum(N) == m2 * v2 * N.y
+    assert p.angular_momentum(O, N) == 0
+    P2.set_vel(N, v3 * N.z)
+    assert p.linear_momentum(N) == m2 * v3 * N.z
+    assert p.angular_momentum(O, N) == m2 * r * v3 * N.x
+    P2.set_vel(N, v1 * N.x + v2 * N.y + v3 * N.z)
+    assert p.linear_momentum(N) == m2 * (v1 * N.x + v2 * N.y + v3 * N.z)
+    assert p.angular_momentum(O, N) == m2 * r * (v3 * N.x - v1 * N.z)
+    p.potential_energy = m * g * h
+    assert p.potential_energy == m * g * h
+    # TODO make the result not be system-dependent
+    assert p.kinetic_energy(
+        N) in [m2 * (v1 ** 2 + v2 ** 2 + v3 ** 2) / 2,
+               m2 * v1 ** 2 / 2 + m2 * v2 ** 2 / 2 + m2 * v3 ** 2 / 2]
+
+
+def test_parallel_axis():
+    N = ReferenceFrame('N')
+    m, a, b = symbols('m, a, b')
+    o = Point('o')
+    p = o.locatenew('p', a * N.x + b * N.y)
+    P = Particle('P', o, m)
+    Ip = P.parallel_axis(p, N)
+    Ip_expected = inertia(N, m * b ** 2, m * a ** 2, m * (a ** 2 + b ** 2),
+                          ixy=-m * a * b)
+    assert Ip == Ip_expected
+
+
+def test_deprecated_set_potential_energy():
+    m, g, h = symbols('m g h')
+    P = Point('P')
+    p = Particle('pa', P, m)
+    with warns_deprecated_sympy():
+        p.set_potential_energy(m * g * h)

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_rigidbody.py

@@ -0,0 +1,184 @@
+from sympy.physics.mechanics import Point, ReferenceFrame, Dyadic, RigidBody
+from sympy.physics.mechanics import dynamicsymbols, outer, inertia, Inertia
+from sympy.physics.mechanics import inertia_of_point_mass
+from sympy import expand, zeros, simplify, symbols
+from sympy.testing.pytest import raises, warns_deprecated_sympy
+
+
+def test_rigidbody_default():
+    # Test default
+    b = RigidBody('B')
+    I = inertia(b.frame, *symbols('B_ixx B_iyy B_izz B_ixy B_iyz B_izx'))
+    assert b.name == 'B'
+    assert b.mass == symbols('B_mass')
+    assert b.masscenter.name == 'B_masscenter'
+    assert b.inertia == (I, b.masscenter)
+    assert b.central_inertia == I
+    assert b.frame.name == 'B_frame'
+    assert b.__str__() == 'B'
+    assert b.__repr__() == (
+        "RigidBody('B', masscenter=B_masscenter, frame=B_frame, mass=B_mass, "
+        "inertia=Inertia(dyadic=B_ixx*(B_frame.x|B_frame.x) + "
+        "B_ixy*(B_frame.x|B_frame.y) + B_izx*(B_frame.x|B_frame.z) + "
+        "B_ixy*(B_frame.y|B_frame.x) + B_iyy*(B_frame.y|B_frame.y) + "
+        "B_iyz*(B_frame.y|B_frame.z) + B_izx*(B_frame.z|B_frame.x) + "
+        "B_iyz*(B_frame.z|B_frame.y) + B_izz*(B_frame.z|B_frame.z), "
+        "point=B_masscenter))")
+
+
+def test_rigidbody():
+    m, m2, v1, v2, v3, omega = symbols('m m2 v1 v2 v3 omega')
+    A = ReferenceFrame('A')
+    A2 = ReferenceFrame('A2')
+    P = Point('P')
+    P2 = Point('P2')
+    I = Dyadic(0)
+    I2 = Dyadic(0)
+    B = RigidBody('B', P, A, m, (I, P))
+    assert B.mass == m
+    assert B.frame == A
+    assert B.masscenter == P
+    assert B.inertia == (I, B.masscenter)
+
+    B.mass = m2
+    B.frame = A2
+    B.masscenter = P2
+    B.inertia = (I2, B.masscenter)
+    raises(TypeError, lambda: RigidBody(P, P, A, m, (I, P)))
+    raises(TypeError, lambda: RigidBody('B', P, P, m, (I, P)))
+    raises(TypeError, lambda: RigidBody('B', P, A, m, (P, P)))
+    raises(TypeError, lambda: RigidBody('B', P, A, m, (I, I)))
+    assert B.__str__() == 'B'
+    assert B.mass == m2
+    assert B.frame == A2
+    assert B.masscenter == P2
+    assert B.inertia == (I2, B.masscenter)
+    assert isinstance(B.inertia, Inertia)
+
+    # Testing linear momentum function assuming A2 is the inertial frame
+    N = ReferenceFrame('N')
+    P2.set_vel(N, v1 * N.x + v2 * N.y + v3 * N.z)
+    assert B.linear_momentum(N) == m2 * (v1 * N.x + v2 * N.y + v3 * N.z)
+
+
+def test_rigidbody2():
+    M, v, r, omega, g, h = dynamicsymbols('M v r omega g h')
+    N = ReferenceFrame('N')
+    b = ReferenceFrame('b')
+    b.set_ang_vel(N, omega * b.x)
+    P = Point('P')
+    I = outer(b.x, b.x)
+    Inertia_tuple = (I, P)
+    B = RigidBody('B', P, b, M, Inertia_tuple)
+    P.set_vel(N, v * b.x)
+    assert B.angular_momentum(P, N) == omega * b.x
+    O = Point('O')
+    O.set_vel(N, v * b.x)
+    P.set_pos(O, r * b.y)
+    assert B.angular_momentum(O, N) == omega * b.x - M*v*r*b.z
+    B.potential_energy = M * g * h
+    assert B.potential_energy == M * g * h
+    assert expand(2 * B.kinetic_energy(N)) == omega**2 + M * v**2
+
+
+def test_rigidbody3():
+    q1, q2, q3, q4 = dynamicsymbols('q1:5')
+    p1, p2, p3 = symbols('p1:4')
+    m = symbols('m')
+
+    A = ReferenceFrame('A')
+    B = A.orientnew('B', 'axis', [q1, A.x])
+    O = Point('O')
+    O.set_vel(A, q2*A.x + q3*A.y + q4*A.z)
+    P = O.locatenew('P', p1*B.x + p2*B.y + p3*B.z)
+    P.v2pt_theory(O, A, B)
+    I = outer(B.x, B.x)
+
+    rb1 = RigidBody('rb1', P, B, m, (I, P))
+    # I_S/O = I_S/S* + I_S*/O
+    rb2 = RigidBody('rb2', P, B, m,
+                    (I + inertia_of_point_mass(m, P.pos_from(O), B), O))
+
+    assert rb1.central_inertia == rb2.central_inertia
+    assert rb1.angular_momentum(O, A) == rb2.angular_momentum(O, A)
+
+
+def test_pendulum_angular_momentum():
+    """Consider a pendulum of length OA = 2a, of mass m as a rigid body of
+    center of mass G (OG = a) which turn around (O,z). The angle between the
+    reference frame R and the rod is q.  The inertia of the body is I =
+    (G,0,ma^2/3,ma^2/3). """
+
+    m, a = symbols('m, a')
+    q = dynamicsymbols('q')
+
+    R = ReferenceFrame('R')
+    R1 = R.orientnew('R1', 'Axis', [q, R.z])
+    R1.set_ang_vel(R, q.diff() * R.z)
+
+    I = inertia(R1, 0, m * a**2 / 3, m * a**2 / 3)
+
+    O = Point('O')
+
+    A = O.locatenew('A', 2*a * R1.x)
+    G = O.locatenew('G', a * R1.x)
+
+    S = RigidBody('S', G, R1, m, (I, G))
+
+    O.set_vel(R, 0)
+    A.v2pt_theory(O, R, R1)
+    G.v2pt_theory(O, R, R1)
+
+    assert (4 * m * a**2 / 3 * q.diff() * R.z -
+            S.angular_momentum(O, R).express(R)) == 0
+
+
+def test_rigidbody_inertia():
+    N = ReferenceFrame('N')
+    m, Ix, Iy, Iz, a, b = symbols('m, I_x, I_y, I_z, a, b')
+    Io = inertia(N, Ix, Iy, Iz)
+    o = Point('o')
+    p = o.locatenew('p', a * N.x + b * N.y)
+    R = RigidBody('R', o, N, m, (Io, p))
+    I_check = inertia(N, Ix - b ** 2 * m, Iy - a ** 2 * m,
+                      Iz - m * (a ** 2 + b ** 2), m * a * b)
+    assert isinstance(R.inertia, Inertia)
+    assert R.inertia == (Io, p)
+    assert R.central_inertia == I_check
+    R.central_inertia = Io
+    assert R.inertia == (Io, o)
+    assert R.central_inertia == Io
+    R.inertia = (Io, p)
+    assert R.inertia == (Io, p)
+    assert R.central_inertia == I_check
+    # parse Inertia object
+    R.inertia = Inertia(Io, o)
+    assert R.inertia == (Io, o)
+
+
+def test_parallel_axis():
+    N = ReferenceFrame('N')
+    m, Ix, Iy, Iz, a, b = symbols('m, I_x, I_y, I_z, a, b')
+    Io = inertia(N, Ix, Iy, Iz)
+    o = Point('o')
+    p = o.locatenew('p', a * N.x + b * N.y)
+    R = RigidBody('R', o, N, m, (Io, o))
+    Ip = R.parallel_axis(p)
+    Ip_expected = inertia(N, Ix + m * b**2, Iy + m * a**2,
+                          Iz + m * (a**2 + b**2), ixy=-m * a * b)
+    assert Ip == Ip_expected
+    # Reference frame from which the parallel axis is viewed should not matter
+    A = ReferenceFrame('A')
+    A.orient_axis(N, N.z, 1)
+    assert simplify(
+        (R.parallel_axis(p, A) - Ip_expected).to_matrix(A)) == zeros(3, 3)
+
+
+def test_deprecated_set_potential_energy():
+    m, g, h = symbols('m g h')
+    A = ReferenceFrame('A')
+    P = Point('P')
+    I = Dyadic(0)
+    B = RigidBody('B', P, A, m, (I, P))
+    with warns_deprecated_sympy():
+        B.set_potential_energy(m*g*h)

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_system.py

@@ -0,0 +1,245 @@
+from sympy import symbols, Matrix, atan, zeros
+from sympy.simplify.simplify import simplify
+from sympy.physics.mechanics import (dynamicsymbols, Particle, Point,
+                                     ReferenceFrame, SymbolicSystem)
+from sympy.testing.pytest import raises
+
+# This class is going to be tested using a simple pendulum set up in x and y
+# coordinates
+x, y, u, v, lam = dynamicsymbols('x y u v lambda')
+m, l, g = symbols('m l g')
+
+# Set up the different forms the equations can take
+#       [1] Explicit form where the kinematics and dynamics are combined
+#           x' = F(x, t, r, p)
+#
+#       [2] Implicit form where the kinematics and dynamics are combined
+#           M(x, p) x' = F(x, t, r, p)
+#
+#       [3] Implicit form where the kinematics and dynamics are separate
+#           M(q, p) u' = F(q, u, t, r, p)
+#           q' = G(q, u, t, r, p)
+dyn_implicit_mat = Matrix([[1, 0, -x/m],
+                           [0, 1, -y/m],
+                           [0, 0, l**2/m]])
+
+dyn_implicit_rhs = Matrix([0, 0, u**2 + v**2 - g*y])
+
+comb_implicit_mat = Matrix([[1, 0, 0, 0, 0],
+                            [0, 1, 0, 0, 0],
+                            [0, 0, 1, 0, -x/m],
+                            [0, 0, 0, 1, -y/m],
+                            [0, 0, 0, 0, l**2/m]])
+
+comb_implicit_rhs = Matrix([u, v, 0, 0, u**2 + v**2 - g*y])
+
+kin_explicit_rhs = Matrix([u, v])
+
+comb_explicit_rhs = comb_implicit_mat.LUsolve(comb_implicit_rhs)
+
+# Set up a body and load to pass into the system
+theta = atan(x/y)
+N = ReferenceFrame('N')
+A = N.orientnew('A', 'Axis', [theta, N.z])
+O = Point('O')
+P = O.locatenew('P', l * A.x)
+
+Pa = Particle('Pa', P, m)
+
+bodies = [Pa]
+loads = [(P, g * m * N.x)]
+
+# Set up some output equations to be given to SymbolicSystem
+# Change to make these fit the pendulum
+PE = symbols("PE")
+out_eqns = {PE: m*g*(l+y)}
+
+# Set up remaining arguments that can be passed to SymbolicSystem
+alg_con = [2]
+alg_con_full = [4]
+coordinates = (x, y, lam)
+speeds = (u, v)
+states = (x, y, u, v, lam)
+coord_idxs = (0, 1)
+speed_idxs = (2, 3)
+
+
+def test_form_1():
+    symsystem1 = SymbolicSystem(states, comb_explicit_rhs,
+                                alg_con=alg_con_full, output_eqns=out_eqns,
+                                coord_idxs=coord_idxs, speed_idxs=speed_idxs,
+                                bodies=bodies, loads=loads)
+
+    assert symsystem1.coordinates == Matrix([x, y])
+    assert symsystem1.speeds == Matrix([u, v])
+    assert symsystem1.states == Matrix([x, y, u, v, lam])
+
+    assert symsystem1.alg_con == [4]
+
+    inter = comb_explicit_rhs
+    assert simplify(symsystem1.comb_explicit_rhs - inter) == zeros(5, 1)
+
+    assert set(symsystem1.dynamic_symbols()) == {y, v, lam, u, x}
+    assert type(symsystem1.dynamic_symbols()) == tuple
+    assert set(symsystem1.constant_symbols()) == {l, g, m}
+    assert type(symsystem1.constant_symbols()) == tuple
+
+    assert symsystem1.output_eqns == out_eqns
+
+    assert symsystem1.bodies == (Pa,)
+    assert symsystem1.loads == ((P, g * m * N.x),)
+
+
+def test_form_2():
+    symsystem2 = SymbolicSystem(coordinates, comb_implicit_rhs, speeds=speeds,
+                                mass_matrix=comb_implicit_mat,
+                                alg_con=alg_con_full, output_eqns=out_eqns,
+                                bodies=bodies, loads=loads)
+
+    assert symsystem2.coordinates == Matrix([x, y, lam])
+    assert symsystem2.speeds == Matrix([u, v])
+    assert symsystem2.states == Matrix([x, y, lam, u, v])
+
+    assert symsystem2.alg_con == [4]
+
+    inter = comb_implicit_rhs
+    assert simplify(symsystem2.comb_implicit_rhs - inter) == zeros(5, 1)
+    assert simplify(symsystem2.comb_implicit_mat-comb_implicit_mat) == zeros(5)
+
+    assert set(symsystem2.dynamic_symbols()) == {y, v, lam, u, x}
+    assert type(symsystem2.dynamic_symbols()) == tuple
+    assert set(symsystem2.constant_symbols()) == {l, g, m}
+    assert type(symsystem2.constant_symbols()) == tuple
+
+    inter = comb_explicit_rhs
+    symsystem2.compute_explicit_form()
+    assert simplify(symsystem2.comb_explicit_rhs - inter) == zeros(5, 1)
+
+
+    assert symsystem2.output_eqns == out_eqns
+
+    assert symsystem2.bodies == (Pa,)
+    assert symsystem2.loads == ((P, g * m * N.x),)
+
+
+def test_form_3():
+    symsystem3 = SymbolicSystem(states, dyn_implicit_rhs,
+                                mass_matrix=dyn_implicit_mat,
+                                coordinate_derivatives=kin_explicit_rhs,
+                                alg_con=alg_con, coord_idxs=coord_idxs,
+                                speed_idxs=speed_idxs, bodies=bodies,
+                                loads=loads)
+
+    assert symsystem3.coordinates == Matrix([x, y])
+    assert symsystem3.speeds == Matrix([u, v])
+    assert symsystem3.states == Matrix([x, y, u, v, lam])
+
+    assert symsystem3.alg_con == [4]
+
+    inter1 = kin_explicit_rhs
+    inter2 = dyn_implicit_rhs
+    assert simplify(symsystem3.kin_explicit_rhs - inter1) == zeros(2, 1)
+    assert simplify(symsystem3.dyn_implicit_mat - dyn_implicit_mat) == zeros(3)
+    assert simplify(symsystem3.dyn_implicit_rhs - inter2) == zeros(3, 1)
+
+    inter = comb_implicit_rhs
+    assert simplify(symsystem3.comb_implicit_rhs - inter) == zeros(5, 1)
+    assert simplify(symsystem3.comb_implicit_mat-comb_implicit_mat) == zeros(5)
+
+    inter = comb_explicit_rhs
+    symsystem3.compute_explicit_form()
+    assert simplify(symsystem3.comb_explicit_rhs - inter) == zeros(5, 1)
+
+    assert set(symsystem3.dynamic_symbols()) == {y, v, lam, u, x}
+    assert type(symsystem3.dynamic_symbols()) == tuple
+    assert set(symsystem3.constant_symbols()) == {l, g, m}
+    assert type(symsystem3.constant_symbols()) == tuple
+
+    assert symsystem3.output_eqns == {}
+
+    assert symsystem3.bodies == (Pa,)
+    assert symsystem3.loads == ((P, g * m * N.x),)
+
+
+def test_property_attributes():
+    symsystem = SymbolicSystem(states, comb_explicit_rhs,
+                               alg_con=alg_con_full, output_eqns=out_eqns,
+                               coord_idxs=coord_idxs, speed_idxs=speed_idxs,
+                               bodies=bodies, loads=loads)
+
+    with raises(AttributeError):
+        symsystem.bodies = 42
+    with raises(AttributeError):
+        symsystem.coordinates = 42
+    with raises(AttributeError):
+        symsystem.dyn_implicit_rhs = 42
+    with raises(AttributeError):
+        symsystem.comb_implicit_rhs = 42
+    with raises(AttributeError):
+        symsystem.loads = 42
+    with raises(AttributeError):
+        symsystem.dyn_implicit_mat = 42
+    with raises(AttributeError):
+        symsystem.comb_implicit_mat = 42
+    with raises(AttributeError):
+        symsystem.kin_explicit_rhs = 42
+    with raises(AttributeError):
+        symsystem.comb_explicit_rhs = 42
+    with raises(AttributeError):
+        symsystem.speeds = 42
+    with raises(AttributeError):
+        symsystem.states = 42
+    with raises(AttributeError):
+        symsystem.alg_con = 42
+
+
+def test_not_specified_errors():
+    """This test will cover errors that arise from trying to access attributes
+    that were not specified upon object creation or were specified on creation
+    and the user tries to recalculate them."""
+    # Trying to access form 2 when form 1 given
+    # Trying to access form 3 when form 2 given
+
+    symsystem1 = SymbolicSystem(states, comb_explicit_rhs)
+
+    with raises(AttributeError):
+        symsystem1.comb_implicit_mat
+    with raises(AttributeError):
+        symsystem1.comb_implicit_rhs
+    with raises(AttributeError):
+        symsystem1.dyn_implicit_mat
+    with raises(AttributeError):
+        symsystem1.dyn_implicit_rhs
+    with raises(AttributeError):
+        symsystem1.kin_explicit_rhs
+    with raises(AttributeError):
+        symsystem1.compute_explicit_form()
+
+    symsystem2 = SymbolicSystem(coordinates, comb_implicit_rhs, speeds=speeds,
+                                mass_matrix=comb_implicit_mat)
+
+    with raises(AttributeError):
+        symsystem2.dyn_implicit_mat
+    with raises(AttributeError):
+        symsystem2.dyn_implicit_rhs
+    with raises(AttributeError):
+        symsystem2.kin_explicit_rhs
+
+    # Attribute error when trying to access coordinates and speeds when only the
+    # states were given.
+    with raises(AttributeError):
+        symsystem1.coordinates
+    with raises(AttributeError):
+        symsystem1.speeds
+
+    # Attribute error when trying to access bodies and loads when they are not
+    # given
+    with raises(AttributeError):
+        symsystem1.bodies
+    with raises(AttributeError):
+        symsystem1.loads
+
+    # Attribute error when trying to access comb_explicit_rhs before it was
+    # calculated
+    with raises(AttributeError):
+        symsystem2.comb_explicit_rhs

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_wrapping_geometry.py

@@ -0,0 +1,363 @@
+"""Tests for the ``sympy.physics.mechanics.wrapping_geometry.py`` module."""
+
+import pytest
+
+from sympy import (
+    Integer,
+    Rational,
+    S,
+    Symbol,
+    acos,
+    cos,
+    pi,
+    sin,
+    sqrt,
+)
+from sympy.core.relational import Eq
+from sympy.physics.mechanics import (
+    Point,
+    ReferenceFrame,
+    WrappingCylinder,
+    WrappingSphere,
+    dynamicsymbols,
+)
+from sympy.simplify.simplify import simplify
+
+
+r = Symbol('r', positive=True)
+x = Symbol('x')
+q = dynamicsymbols('q')
+N = ReferenceFrame('N')
+
+
+class TestWrappingSphere:
+
+    @staticmethod
+    def test_valid_constructor():
+        r = Symbol('r', positive=True)
+        pO = Point('pO')
+        sphere = WrappingSphere(r, pO)
+        assert isinstance(sphere, WrappingSphere)
+        assert hasattr(sphere, 'radius')
+        assert sphere.radius == r
+        assert hasattr(sphere, 'point')
+        assert sphere.point == pO
+
+    @staticmethod
+    @pytest.mark.parametrize('position', [S.Zero, Integer(2)*r*N.x])
+    def test_geodesic_length_point_not_on_surface_invalid(position):
+        r = Symbol('r', positive=True)
+        pO = Point('pO')
+        sphere = WrappingSphere(r, pO)
+
+        p1 = Point('p1')
+        p1.set_pos(pO, position)
+        p2 = Point('p2')
+        p2.set_pos(pO, position)
+
+        error_msg = r'point .* does not lie on the surface of'
+        with pytest.raises(ValueError, match=error_msg):
+            sphere.geodesic_length(p1, p2)
+
+    @staticmethod
+    @pytest.mark.parametrize(
+        'position_1, position_2, expected',
+        [
+            (r*N.x, r*N.x, S.Zero),
+            (r*N.x, r*N.y, S.Half*pi*r),
+            (r*N.x, r*-N.x, pi*r),
+            (r*-N.x, r*N.x, pi*r),
+            (r*N.x, r*sqrt(2)*S.Half*(N.x + N.y), Rational(1, 4)*pi*r),
+            (
+                r*sqrt(2)*S.Half*(N.x + N.y),
+                r*sqrt(3)*Rational(1, 3)*(N.x + N.y + N.z),
+                r*acos(sqrt(6)*Rational(1, 3)),
+            ),
+        ]
+    )
+    def test_geodesic_length(position_1, position_2, expected):
+        r = Symbol('r', positive=True)
+        pO = Point('pO')
+        sphere = WrappingSphere(r, pO)
+
+        p1 = Point('p1')
+        p1.set_pos(pO, position_1)
+        p2 = Point('p2')
+        p2.set_pos(pO, position_2)
+
+        assert simplify(Eq(sphere.geodesic_length(p1, p2), expected))
+
+    @staticmethod
+    @pytest.mark.parametrize(
+        'position_1, position_2, vector_1, vector_2',
+        [
+            (r * N.x, r * N.y, N.y, N.x),
+            (r * N.x, -r * N.y, -N.y, N.x),
+            (
+                r * N.y,
+                sqrt(2)/2 * r * N.x - sqrt(2)/2 * r * N.y,
+                N.x,
+                sqrt(2)/2 * N.x + sqrt(2)/2 * N.y,
+            ),
+            (
+                r * N.x,
+                r / 2 * N.x + sqrt(3)/2 * r * N.y,
+                N.y,
+                sqrt(3)/2 * N.x - 1/2 * N.y,
+            ),
+            (
+                r * N.x,
+                sqrt(2)/2 * r * N.x + sqrt(2)/2 * r * N.y,
+                N.y,
+                sqrt(2)/2 * N.x - sqrt(2)/2 * N.y,
+            ),
+        ]
+    )
+    def test_geodesic_end_vectors(position_1, position_2, vector_1, vector_2):
+        r = Symbol('r', positive=True)
+        pO = Point('pO')
+        sphere = WrappingSphere(r, pO)
+
+        p1 = Point('p1')
+        p1.set_pos(pO, position_1)
+        p2 = Point('p2')
+        p2.set_pos(pO, position_2)
+
+        expected = (vector_1, vector_2)
+
+        assert sphere.geodesic_end_vectors(p1, p2) == expected
+
+    @staticmethod
+    @pytest.mark.parametrize(
+        'position',
+        [r * N.x, r * cos(q) * N.x + r * sin(q) * N.y]
+    )
+    def test_geodesic_end_vectors_invalid_coincident(position):
+        r = Symbol('r', positive=True)
+        pO = Point('pO')
+        sphere = WrappingSphere(r, pO)
+
+        p1 = Point('p1')
+        p1.set_pos(pO, position)
+        p2 = Point('p2')
+        p2.set_pos(pO, position)
+
+        with pytest.raises(ValueError):
+            _ = sphere.geodesic_end_vectors(p1, p2)
+
+    @staticmethod
+    @pytest.mark.parametrize(
+        'position_1, position_2',
+        [
+            (r * N.x, -r * N.x),
+            (-r * N.y, r * N.y),
+            (
+                r * cos(q) * N.x + r * sin(q) * N.y,
+                -r * cos(q) * N.x - r * sin(q) * N.y,
+            )
+        ]
+    )
+    def test_geodesic_end_vectors_invalid_diametrically_opposite(
+        position_1,
+        position_2,
+    ):
+        r = Symbol('r', positive=True)
+        pO = Point('pO')
+        sphere = WrappingSphere(r, pO)
+
+        p1 = Point('p1')
+        p1.set_pos(pO, position_1)
+        p2 = Point('p2')
+        p2.set_pos(pO, position_2)
+
+        with pytest.raises(ValueError):
+            _ = sphere.geodesic_end_vectors(p1, p2)
+
+
+class TestWrappingCylinder:
+
+    @staticmethod
+    def test_valid_constructor():
+        N = ReferenceFrame('N')
+        r = Symbol('r', positive=True)
+        pO = Point('pO')
+        cylinder = WrappingCylinder(r, pO, N.x)
+        assert isinstance(cylinder, WrappingCylinder)
+        assert hasattr(cylinder, 'radius')
+        assert cylinder.radius == r
+        assert hasattr(cylinder, 'point')
+        assert cylinder.point == pO
+        assert hasattr(cylinder, 'axis')
+        assert cylinder.axis == N.x
+
+    @staticmethod
+    @pytest.mark.parametrize(
+        'position, expected',
+        [
+            (S.Zero, False),
+            (r*N.y, True),
+            (r*N.z, True),
+            (r*(N.y + N.z).normalize(), True),
+            (Integer(2)*r*N.y, False),
+            (r*(N.x + N.y), True),
+            (r*(Integer(2)*N.x + N.y), True),
+            (Integer(2)*N.x + r*(Integer(2)*N.y + N.z).normalize(), True),
+            (r*(cos(q)*N.y + sin(q)*N.z), True)
+        ]
+    )
+    def test_point_is_on_surface(position, expected):
+        r = Symbol('r', positive=True)
+        pO = Point('pO')
+        cylinder = WrappingCylinder(r, pO, N.x)
+
+        p1 = Point('p1')
+        p1.set_pos(pO, position)
+
+        assert cylinder.point_on_surface(p1) is expected
+
+    @staticmethod
+    @pytest.mark.parametrize('position', [S.Zero, Integer(2)*r*N.y])
+    def test_geodesic_length_point_not_on_surface_invalid(position):
+        r = Symbol('r', positive=True)
+        pO = Point('pO')
+        cylinder = WrappingCylinder(r, pO, N.x)
+
+        p1 = Point('p1')
+        p1.set_pos(pO, position)
+        p2 = Point('p2')
+        p2.set_pos(pO, position)
+
+        error_msg = r'point .* does not lie on the surface of'
+        with pytest.raises(ValueError, match=error_msg):
+            cylinder.geodesic_length(p1, p2)
+
+    @staticmethod
+    @pytest.mark.parametrize(
+        'axis, position_1, position_2, expected',
+        [
+            (N.x, r*N.y, r*N.y, S.Zero),
+            (N.x, r*N.y, N.x + r*N.y, S.One),
+            (N.x, r*N.y, -x*N.x + r*N.y, sqrt(x**2)),
+            (-N.x, r*N.y, x*N.x + r*N.y, sqrt(x**2)),
+            (N.x, r*N.y, r*N.z, S.Half*pi*sqrt(r**2)),
+            (-N.x, r*N.y, r*N.z, Integer(3)*S.Half*pi*sqrt(r**2)),
+            (N.x, r*N.z, r*N.y, Integer(3)*S.Half*pi*sqrt(r**2)),
+            (-N.x, r*N.z, r*N.y, S.Half*pi*sqrt(r**2)),
+            (N.x, r*N.y, r*(cos(q)*N.y + sin(q)*N.z), sqrt(r**2*q**2)),
+            (
+                -N.x, r*N.y,
+                r*(cos(q)*N.y + sin(q)*N.z),
+                sqrt(r**2*(Integer(2)*pi - q)**2),
+            ),
+        ]
+    )
+    def test_geodesic_length(axis, position_1, position_2, expected):
+        r = Symbol('r', positive=True)
+        pO = Point('pO')
+        cylinder = WrappingCylinder(r, pO, axis)
+
+        p1 = Point('p1')
+        p1.set_pos(pO, position_1)
+        p2 = Point('p2')
+        p2.set_pos(pO, position_2)
+
+        assert simplify(Eq(cylinder.geodesic_length(p1, p2), expected))
+
+    @staticmethod
+    @pytest.mark.parametrize(
+        'axis, position_1, position_2, vector_1, vector_2',
+        [
+            (N.z, r * N.x, r * N.y, N.y, N.x),
+            (N.z, r * N.x, -r * N.x, N.y, N.y),
+            (N.z, -r * N.x, r * N.x, -N.y, -N.y),
+            (-N.z, r * N.x, -r * N.x, -N.y, -N.y),
+            (-N.z, -r * N.x, r * N.x, N.y, N.y),
+            (N.z, r * N.x, -r * N.y, N.y, -N.x),
+            (
+                N.z,
+                r * N.y,
+                sqrt(2)/2 * r * N.x - sqrt(2)/2 * r * N.y,
+                - N.x,
+                - sqrt(2)/2 * N.x - sqrt(2)/2 * N.y,
+            ),
+            (
+                N.z,
+                r * N.x,
+                r / 2 * N.x + sqrt(3)/2 * r * N.y,
+                N.y,
+                sqrt(3)/2 * N.x - 1/2 * N.y,
+            ),
+            (
+                N.z,
+                r * N.x,
+                sqrt(2)/2 * r * N.x + sqrt(2)/2 * r * N.y,
+                N.y,
+                sqrt(2)/2 * N.x - sqrt(2)/2 * N.y,
+            ),
+            (
+                N.z,
+                r * N.x,
+                r * N.x + N.z,
+                N.z,
+                -N.z,
+            ),
+            (
+                N.z,
+                r * N.x,
+                r * N.y + pi/2 * r * N.z,
+                sqrt(2)/2 * N.y + sqrt(2)/2 * N.z,
+                sqrt(2)/2 * N.x - sqrt(2)/2 * N.z,
+            ),
+            (
+                N.z,
+                r * N.x,
+                r * cos(q) * N.x + r * sin(q) * N.y,
+                N.y,
+                sin(q) * N.x - cos(q) * N.y,
+            ),
+        ]
+    )
+    def test_geodesic_end_vectors(
+        axis,
+        position_1,
+        position_2,
+        vector_1,
+        vector_2,
+    ):
+        r = Symbol('r', positive=True)
+        pO = Point('pO')
+        cylinder = WrappingCylinder(r, pO, axis)
+
+        p1 = Point('p1')
+        p1.set_pos(pO, position_1)
+        p2 = Point('p2')
+        p2.set_pos(pO, position_2)
+
+        expected = (vector_1, vector_2)
+        end_vectors = tuple(
+            end_vector.simplify()
+            for end_vector in cylinder.geodesic_end_vectors(p1, p2)
+        )
+
+        assert end_vectors == expected
+
+    @staticmethod
+    @pytest.mark.parametrize(
+        'axis, position',
+        [
+            (N.z, r * N.x),
+            (N.z, r * cos(q) * N.x + r * sin(q) * N.y + N.z),
+        ]
+    )
+    def test_geodesic_end_vectors_invalid_coincident(axis, position):
+        r = Symbol('r', positive=True)
+        pO = Point('pO')
+        cylinder = WrappingCylinder(r, pO, axis)
+
+        p1 = Point('p1')
+        p1.set_pos(pO, position)
+        p2 = Point('p2')
+        p2.set_pos(pO, position)
+
+        with pytest.raises(ValueError):
+            _ = cylinder.geodesic_end_vectors(p1, p2)

evalkit_internvl/lib/python3.10/site-packages/sympy/physics/mechanics/wrapping_geometry.py

@@ -0,0 +1,641 @@
+"""Geometry objects for use by wrapping pathways."""
+
+from abc import ABC, abstractmethod
+
+from sympy import Integer, acos, pi, sqrt, sympify, tan
+from sympy.core.relational import Eq
+from sympy.functions.elementary.trigonometric import atan2
+from sympy.polys.polytools import cancel
+from sympy.physics.vector import Vector, dot
+from sympy.simplify.simplify import trigsimp
+
+
+__all__ = [
+    'WrappingGeometryBase',
+    'WrappingCylinder',
+    'WrappingSphere',
+]
+
+
+class WrappingGeometryBase(ABC):
+    """Abstract base class for all geometry classes to inherit from.
+
+    Notes
+    =====
+
+    Instances of this class cannot be directly instantiated by users. However,
+    it can be used to created custom geometry types through subclassing.
+
+    """
+
+    @property
+    @abstractmethod
+    def point(cls):
+        """The point with which the geometry is associated."""
+        pass
+
+    @abstractmethod
+    def point_on_surface(self, point):
+        """Returns ``True`` if a point is on the geometry's surface.
+
+        Parameters
+        ==========
+        point : Point
+            The point for which it's to be ascertained if it's on the
+            geometry's surface or not.
+
+        """
+        pass
+
+    @abstractmethod
+    def geodesic_length(self, point_1, point_2):
+        """Returns the shortest distance between two points on a geometry's
+        surface.
+
+        Parameters
+        ==========
+
+        point_1 : Point
+            The point from which the geodesic length should be calculated.
+        point_2 : Point
+            The point to which the geodesic length should be calculated.
+
+        """
+        pass
+
+    @abstractmethod
+    def geodesic_end_vectors(self, point_1, point_2):
+        """The vectors parallel to the geodesic at the two end points.
+
+        Parameters
+        ==========
+
+        point_1 : Point
+            The point from which the geodesic originates.
+        point_2 : Point
+            The point at which the geodesic terminates.
+
+        """
+        pass
+
+    def __repr__(self):
+        """Default representation of a geometry object."""
+        return f'{self.__class__.__name__}()'
+
+
+class WrappingSphere(WrappingGeometryBase):
+    """A solid spherical object.
+
+    Explanation
+    ===========
+
+    A wrapping geometry that allows for circular arcs to be defined between
+    pairs of points. These paths are always geodetic (the shortest possible).
+
+    Examples
+    ========
+
+    To create a ``WrappingSphere`` instance, a ``Symbol`` denoting its radius
+    and ``Point`` at which its center will be located are needed:
+
+    >>> from sympy import symbols
+    >>> from sympy.physics.mechanics import Point, WrappingSphere
+    >>> r = symbols('r')
+    >>> pO = Point('pO')
+
+    A sphere with radius ``r`` centered on ``pO`` can be instantiated with:
+
+    >>> WrappingSphere(r, pO)
+    WrappingSphere(radius=r, point=pO)
+
+    Parameters
+    ==========
+
+    radius : Symbol
+        Radius of the sphere. This symbol must represent a value that is
+        positive and constant, i.e. it cannot be a dynamic symbol, nor can it
+        be an expression.
+    point : Point
+        A point at which the sphere is centered.
+
+    See Also
+    ========
+
+    WrappingCylinder: Cylindrical geometry where the wrapping direction can be
+        defined.
+
+    """
+
+    def __init__(self, radius, point):
+        """Initializer for ``WrappingSphere``.
+
+        Parameters
+        ==========
+
+        radius : Symbol
+            The radius of the sphere.
+        point : Point
+            A point on which the sphere is centered.
+
+        """
+        self.radius = radius
+        self.point = point
+
+    @property
+    def radius(self):
+        """Radius of the sphere."""
+        return self._radius
+
+    @radius.setter
+    def radius(self, radius):
+        self._radius = radius
+
+    @property
+    def point(self):
+        """A point on which the sphere is centered."""
+        return self._point
+
+    @point.setter
+    def point(self, point):
+        self._point = point
+
+    def point_on_surface(self, point):
+        """Returns ``True`` if a point is on the sphere's surface.
+
+        Parameters
+        ==========
+
+        point : Point
+            The point for which it's to be ascertained if it's on the sphere's
+            surface or not. This point's position relative to the sphere's
+            center must be a simple expression involving the radius of the
+            sphere, otherwise this check will likely not work.
+
+        """
+        point_vector = point.pos_from(self.point)
+        if isinstance(point_vector, Vector):
+            point_radius_squared = dot(point_vector, point_vector)
+        else:
+            point_radius_squared = point_vector**2
+        return Eq(point_radius_squared, self.radius**2) == True
+
+    def geodesic_length(self, point_1, point_2):
+        r"""Returns the shortest distance between two points on the sphere's
+        surface.
+
+        Explanation
+        ===========
+
+        The geodesic length, i.e. the shortest arc along the surface of a
+        sphere, connecting two points can be calculated using the formula:
+
+        .. math::
+
+           l = \arccos\left(\mathbf{v}_1 \cdot \mathbf{v}_2\right)
+
+        where $\mathbf{v}_1$ and $\mathbf{v}_2$ are the unit vectors from the
+        sphere's center to the first and second points on the sphere's surface
+        respectively. Note that the actual path that the geodesic will take is
+        undefined when the two points are directly opposite one another.
+
+        Examples
+        ========
+
+        A geodesic length can only be calculated between two points on the
+        sphere's surface. Firstly, a ``WrappingSphere`` instance must be
+        created along with two points that will lie on its surface:
+
+        >>> from sympy import symbols
+        >>> from sympy.physics.mechanics import (Point, ReferenceFrame,
+        ...     WrappingSphere)
+        >>> N = ReferenceFrame('N')
+        >>> r = symbols('r')
+        >>> pO = Point('pO')
+        >>> pO.set_vel(N, 0)
+        >>> sphere = WrappingSphere(r, pO)
+        >>> p1 = Point('p1')
+        >>> p2 = Point('p2')
+
+        Let's assume that ``p1`` lies at a distance of ``r`` in the ``N.x``
+        direction from ``pO`` and that ``p2`` is located on the sphere's
+        surface in the ``N.y + N.z`` direction from ``pO``. These positions can
+        be set with:
+
+        >>> p1.set_pos(pO, r*N.x)
+        >>> p1.pos_from(pO)
+        r*N.x
+        >>> p2.set_pos(pO, r*(N.y + N.z).normalize())
+        >>> p2.pos_from(pO)
+        sqrt(2)*r/2*N.y + sqrt(2)*r/2*N.z
+
+        The geodesic length, which is in this case is a quarter of the sphere's
+        circumference, can be calculated using the ``geodesic_length`` method:
+
+        >>> sphere.geodesic_length(p1, p2)
+        pi*r/2
+
+        If the ``geodesic_length`` method is passed an argument, the ``Point``
+        that doesn't lie on the sphere's surface then a ``ValueError`` is
+        raised because it's not possible to calculate a value in this case.
+
+        Parameters
+        ==========
+
+        point_1 : Point
+            Point from which the geodesic length should be calculated.
+        point_2 : Point
+            Point to which the geodesic length should be calculated.
+
+        """
+        for point in (point_1, point_2):
+            if not self.point_on_surface(point):
+                msg = (
+                    f'Geodesic length cannot be calculated as point {point} '
+                    f'with radius {point.pos_from(self.point).magnitude()} '
+                    f'from the sphere\'s center {self.point} does not lie on '
+                    f'the surface of {self} with radius {self.radius}.'
+                )
+                raise ValueError(msg)
+        point_1_vector = point_1.pos_from(self.point).normalize()
+        point_2_vector = point_2.pos_from(self.point).normalize()
+        central_angle = acos(point_2_vector.dot(point_1_vector))
+        geodesic_length = self.radius*central_angle
+        return geodesic_length
+
+    def geodesic_end_vectors(self, point_1, point_2):
+        """The vectors parallel to the geodesic at the two end points.
+
+        Parameters
+        ==========
+
+        point_1 : Point
+            The point from which the geodesic originates.
+        point_2 : Point
+            The point at which the geodesic terminates.
+
+        """
+        pA, pB = point_1, point_2
+        pO = self.point
+        pA_vec = pA.pos_from(pO)
+        pB_vec = pB.pos_from(pO)
+
+        if pA_vec.cross(pB_vec) == 0:
+            msg = (
+                f'Can\'t compute geodesic end vectors for the pair of points '
+                f'{pA} and {pB} on a sphere {self} as they are diametrically '
+                f'opposed, thus the geodesic is not defined.'
+            )
+            raise ValueError(msg)
+
+        return (
+            pA_vec.cross(pB.pos_from(pA)).cross(pA_vec).normalize(),
+            pB_vec.cross(pA.pos_from(pB)).cross(pB_vec).normalize(),
+        )
+
+    def __repr__(self):
+        """Representation of a ``WrappingSphere``."""
+        return (
+            f'{self.__class__.__name__}(radius={self.radius}, '
+            f'point={self.point})'
+        )
+
+
+class WrappingCylinder(WrappingGeometryBase):
+    """A solid (infinite) cylindrical object.
+
+    Explanation
+    ===========
+
+    A wrapping geometry that allows for circular arcs to be defined between
+    pairs of points. These paths are always geodetic (the shortest possible) in
+    the sense that they will be a straight line on the unwrapped cylinder's
+    surface. However, it is also possible for a direction to be specified, i.e.
+    paths can be influenced such that they either wrap along the shortest side
+    or the longest side of the cylinder. To define these directions, rotations
+    are in the positive direction following the right-hand rule.
+
+    Examples
+    ========
+
+    To create a ``WrappingCylinder`` instance, a ``Symbol`` denoting its
+    radius, a ``Vector`` defining its axis, and a ``Point`` through which its
+    axis passes are needed:
+
+    >>> from sympy import symbols
+    >>> from sympy.physics.mechanics import (Point, ReferenceFrame,
+    ...     WrappingCylinder)
+    >>> N = ReferenceFrame('N')
+    >>> r = symbols('r')
+    >>> pO = Point('pO')
+    >>> ax = N.x
+
+    A cylinder with radius ``r``, and axis parallel to ``N.x`` passing through
+    ``pO`` can be instantiated with:
+
+    >>> WrappingCylinder(r, pO, ax)
+    WrappingCylinder(radius=r, point=pO, axis=N.x)
+
+    Parameters
+    ==========
+
+    radius : Symbol
+        The radius of the cylinder.
+    point : Point
+        A point through which the cylinder's axis passes.
+    axis : Vector
+        The axis along which the cylinder is aligned.
+
+    See Also
+    ========
+
+    WrappingSphere: Spherical geometry where the wrapping direction is always
+        geodetic.
+
+    """
+
+    def __init__(self, radius, point, axis):
+        """Initializer for ``WrappingCylinder``.
+
+        Parameters
+        ==========
+
+        radius : Symbol
+            The radius of the cylinder. This symbol must represent a value that
+            is positive and constant, i.e. it cannot be a dynamic symbol.
+        point : Point
+            A point through which the cylinder's axis passes.
+        axis : Vector
+            The axis along which the cylinder is aligned.
+
+        """
+        self.radius = radius
+        self.point = point
+        self.axis = axis
+
+    @property
+    def radius(self):
+        """Radius of the cylinder."""
+        return self._radius
+
+    @radius.setter
+    def radius(self, radius):
+        self._radius = radius
+
+    @property
+    def point(self):
+        """A point through which the cylinder's axis passes."""
+        return self._point
+
+    @point.setter
+    def point(self, point):
+        self._point = point
+
+    @property
+    def axis(self):
+        """Axis along which the cylinder is aligned."""
+        return self._axis
+
+    @axis.setter
+    def axis(self, axis):
+        self._axis = axis.normalize()
+
+    def point_on_surface(self, point):
+        """Returns ``True`` if a point is on the cylinder's surface.
+
+        Parameters
+        ==========
+
+        point : Point
+            The point for which it's to be ascertained if it's on the
+            cylinder's surface or not. This point's position relative to the
+            cylinder's axis must be a simple expression involving the radius of
+            the sphere, otherwise this check will likely not work.
+
+        """
+        relative_position = point.pos_from(self.point)
+        parallel = relative_position.dot(self.axis) * self.axis
+        point_vector = relative_position - parallel
+        if isinstance(point_vector, Vector):
+            point_radius_squared = dot(point_vector, point_vector)
+        else:
+            point_radius_squared = point_vector**2
+        return Eq(trigsimp(point_radius_squared), self.radius**2) == True
+
+    def geodesic_length(self, point_1, point_2):
+        """The shortest distance between two points on a geometry's surface.
+
+        Explanation
+        ===========
+
+        The geodesic length, i.e. the shortest arc along the surface of a
+        cylinder, connecting two points. It can be calculated using Pythagoras'
+        theorem. The first short side is the distance between the two points on
+        the cylinder's surface parallel to the cylinder's axis. The second
+        short side is the arc of a circle between the two points of the
+        cylinder's surface perpendicular to the cylinder's axis. The resulting
+        hypotenuse is the geodesic length.
+
+        Examples
+        ========
+
+        A geodesic length can only be calculated between two points on the
+        cylinder's surface. Firstly, a ``WrappingCylinder`` instance must be
+        created along with two points that will lie on its surface:
+
+        >>> from sympy import symbols, cos, sin
+        >>> from sympy.physics.mechanics import (Point, ReferenceFrame,
+        ...     WrappingCylinder, dynamicsymbols)
+        >>> N = ReferenceFrame('N')
+        >>> r = symbols('r')
+        >>> pO = Point('pO')
+        >>> pO.set_vel(N, 0)
+        >>> cylinder = WrappingCylinder(r, pO, N.x)
+        >>> p1 = Point('p1')
+        >>> p2 = Point('p2')
+
+        Let's assume that ``p1`` is located at ``N.x + r*N.y`` relative to
+        ``pO`` and that ``p2`` is located at ``r*(cos(q)*N.y + sin(q)*N.z)``
+        relative to ``pO``, where ``q(t)`` is a generalized coordinate
+        specifying the angle rotated around the ``N.x`` axis according to the
+        right-hand rule where ``N.y`` is zero. These positions can be set with:
+
+        >>> q = dynamicsymbols('q')
+        >>> p1.set_pos(pO, N.x + r*N.y)
+        >>> p1.pos_from(pO)
+        N.x + r*N.y
+        >>> p2.set_pos(pO, r*(cos(q)*N.y + sin(q)*N.z).normalize())
+        >>> p2.pos_from(pO).simplify()
+        r*cos(q(t))*N.y + r*sin(q(t))*N.z
+
+        The geodesic length, which is in this case a is the hypotenuse of a
+        right triangle where the other two side lengths are ``1`` (parallel to
+        the cylinder's axis) and ``r*q(t)`` (parallel to the cylinder's cross
+        section), can be calculated using the ``geodesic_length`` method:
+
+        >>> cylinder.geodesic_length(p1, p2).simplify()
+        sqrt(r**2*q(t)**2 + 1)
+
+        If the ``geodesic_length`` method is passed an argument ``Point`` that
+        doesn't lie on the sphere's surface then a ``ValueError`` is raised
+        because it's not possible to calculate a value in this case.
+
+        Parameters
+        ==========
+
+        point_1 : Point
+            Point from which the geodesic length should be calculated.
+        point_2 : Point
+            Point to which the geodesic length should be calculated.
+
+        """
+        for point in (point_1, point_2):
+            if not self.point_on_surface(point):
+                msg = (
+                    f'Geodesic length cannot be calculated as point {point} '
+                    f'with radius {point.pos_from(self.point).magnitude()} '
+                    f'from the cylinder\'s center {self.point} does not lie on '
+                    f'the surface of {self} with radius {self.radius} and axis '
+                    f'{self.axis}.'
+                )
+                raise ValueError(msg)
+
+        relative_position = point_2.pos_from(point_1)
+        parallel_length = relative_position.dot(self.axis)
+
+        point_1_relative_position = point_1.pos_from(self.point)
+        point_1_perpendicular_vector = (
+            point_1_relative_position
+            - point_1_relative_position.dot(self.axis)*self.axis
+        ).normalize()
+
+        point_2_relative_position = point_2.pos_from(self.point)
+        point_2_perpendicular_vector = (
+            point_2_relative_position
+            - point_2_relative_position.dot(self.axis)*self.axis
+        ).normalize()
+
+        central_angle = _directional_atan(
+            cancel(point_1_perpendicular_vector
+                .cross(point_2_perpendicular_vector)
+                .dot(self.axis)),
+            cancel(point_1_perpendicular_vector.dot(point_2_perpendicular_vector)),
+        )
+
+        planar_arc_length = self.radius*central_angle
+        geodesic_length = sqrt(parallel_length**2 + planar_arc_length**2)
+        return geodesic_length
+
+    def geodesic_end_vectors(self, point_1, point_2):
+        """The vectors parallel to the geodesic at the two end points.
+
+        Parameters
+        ==========
+
+        point_1 : Point
+            The point from which the geodesic originates.
+        point_2 : Point
+            The point at which the geodesic terminates.
+
+        """
+        point_1_from_origin_point = point_1.pos_from(self.point)
+        point_2_from_origin_point = point_2.pos_from(self.point)
+
+        if point_1_from_origin_point == point_2_from_origin_point:
+            msg = (
+                f'Cannot compute geodesic end vectors for coincident points '
+                f'{point_1} and {point_2} as no geodesic exists.'
+            )
+            raise ValueError(msg)
+
+        point_1_parallel = point_1_from_origin_point.dot(self.axis) * self.axis
+        point_2_parallel = point_2_from_origin_point.dot(self.axis) * self.axis
+        point_1_normal = (point_1_from_origin_point - point_1_parallel)
+        point_2_normal = (point_2_from_origin_point - point_2_parallel)
+
+        if point_1_normal == point_2_normal:
+            point_1_perpendicular = Vector(0)
+            point_2_perpendicular = Vector(0)
+        else:
+            point_1_perpendicular = self.axis.cross(point_1_normal).normalize()
+            point_2_perpendicular = -self.axis.cross(point_2_normal).normalize()
+
+        geodesic_length = self.geodesic_length(point_1, point_2)
+        relative_position = point_2.pos_from(point_1)
+        parallel_length = relative_position.dot(self.axis)
+        planar_arc_length = sqrt(geodesic_length**2 - parallel_length**2)
+
+        point_1_vector = (
+            planar_arc_length * point_1_perpendicular
+            + parallel_length * self.axis
+        ).normalize()
+        point_2_vector = (
+            planar_arc_length * point_2_perpendicular
+            - parallel_length * self.axis
+        ).normalize()
+
+        return (point_1_vector, point_2_vector)
+
+    def __repr__(self):
+        """Representation of a ``WrappingCylinder``."""
+        return (
+            f'{self.__class__.__name__}(radius={self.radius}, '
+            f'point={self.point}, axis={self.axis})'
+        )
+
+
+def _directional_atan(numerator, denominator):
+    """Compute atan in a directional sense as required for geodesics.
+
+    Explanation
+    ===========
+
+    To be able to control the direction of the geodesic length along the
+    surface of a cylinder a dedicated arctangent function is needed that
+    properly handles the directionality of different case. This function
+    ensures that the central angle is always positive but shifting the case
+    where ``atan2`` would return a negative angle to be centered around
+    ``2*pi``.
+
+    Notes
+    =====
+
+    This function only handles very specific cases, i.e. the ones that are
+    expected to be encountered when calculating symbolic geodesics on uniformly
+    curved surfaces. As such, ``NotImplemented`` errors can be raised in many
+    cases. This function is named with a leader underscore to indicate that it
+    only aims to provide very specific functionality within the private scope
+    of this module.
+
+    """
+
+    if numerator.is_number and denominator.is_number:
+        angle = atan2(numerator, denominator)
+        if angle < 0:
+            angle += 2 * pi
+    elif numerator.is_number:
+        msg = (
+            f'Cannot compute a directional atan when the numerator {numerator} '
+            f'is numeric and the denominator {denominator} is symbolic.'
+        )
+        raise NotImplementedError(msg)
+    elif denominator.is_number:
+        msg = (
+            f'Cannot compute a directional atan when the numerator {numerator} '
+            f'is symbolic and the denominator {denominator} is numeric.'
+        )
+        raise NotImplementedError(msg)
+    else:
+        ratio = sympify(trigsimp(numerator / denominator))
+        if isinstance(ratio, tan):
+            angle = ratio.args[0]
+        elif (
+            ratio.is_Mul
+            and ratio.args[0] == Integer(-1)
+            and isinstance(ratio.args[1], tan)
+        ):
+            angle = 2 * pi - ratio.args[1].args[0]
+        else:
+            msg = f'Cannot compute a directional atan for the value {ratio}.'
+            raise NotImplementedError(msg)
+
+    return angle

evalkit_tf437/lib/python3.10/site-packages/diffusers/commands/__init__.py

@@ -0,0 +1,27 @@
+# Copyright 2024 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from abc import ABC, abstractmethod
+from argparse import ArgumentParser
+
+
+class BaseDiffusersCLICommand(ABC):
+    @staticmethod
+    @abstractmethod
+    def register_subcommand(parser: ArgumentParser):
+        raise NotImplementedError()
+
+    @abstractmethod
+    def run(self):
+        raise NotImplementedError()

evalkit_tf437/lib/python3.10/site-packages/diffusers/commands/diffusers_cli.py

@@ -0,0 +1,43 @@
+#!/usr/bin/env python
+# Copyright 2024 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from argparse import ArgumentParser
+
+from .env import EnvironmentCommand
+from .fp16_safetensors import FP16SafetensorsCommand
+
+
+def main():
+    parser = ArgumentParser("Diffusers CLI tool", usage="diffusers-cli <command> [<args>]")
+    commands_parser = parser.add_subparsers(help="diffusers-cli command helpers")
+
+    # Register commands
+    EnvironmentCommand.register_subcommand(commands_parser)
+    FP16SafetensorsCommand.register_subcommand(commands_parser)
+
+    # Let's go
+    args = parser.parse_args()
+
+    if not hasattr(args, "func"):
+        parser.print_help()
+        exit(1)
+
+    # Run
+    service = args.func(args)
+    service.run()
+
+
+if __name__ == "__main__":
+    main()

evalkit_tf437/lib/python3.10/site-packages/diffusers/commands/env.py

@@ -0,0 +1,84 @@
+# Copyright 2024 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import platform
+from argparse import ArgumentParser
+
+import huggingface_hub
+
+from .. import __version__ as version
+from ..utils import is_accelerate_available, is_torch_available, is_transformers_available, is_xformers_available
+from . import BaseDiffusersCLICommand
+
+
+def info_command_factory(_):
+    return EnvironmentCommand()
+
+
+class EnvironmentCommand(BaseDiffusersCLICommand):
+    @staticmethod
+    def register_subcommand(parser: ArgumentParser):
+        download_parser = parser.add_parser("env")
+        download_parser.set_defaults(func=info_command_factory)
+
+    def run(self):
+        hub_version = huggingface_hub.__version__
+
+        pt_version = "not installed"
+        pt_cuda_available = "NA"
+        if is_torch_available():
+            import torch
+
+            pt_version = torch.__version__
+            pt_cuda_available = torch.cuda.is_available()
+
+        transformers_version = "not installed"
+        if is_transformers_available():
+            import transformers
+
+            transformers_version = transformers.__version__
+
+        accelerate_version = "not installed"
+        if is_accelerate_available():
+            import accelerate
+
+            accelerate_version = accelerate.__version__
+
+        xformers_version = "not installed"
+        if is_xformers_available():
+            import xformers
+
+            xformers_version = xformers.__version__
+
+        info = {
+            "`diffusers` version": version,
+            "Platform": platform.platform(),
+            "Python version": platform.python_version(),
+            "PyTorch version (GPU?)": f"{pt_version} ({pt_cuda_available})",
+            "Huggingface_hub version": hub_version,
+            "Transformers version": transformers_version,
+            "Accelerate version": accelerate_version,
+            "xFormers version": xformers_version,
+            "Using GPU in script?": "<fill in>",
+            "Using distributed or parallel set-up in script?": "<fill in>",
+        }
+
+        print("\nCopy-and-paste the text below in your GitHub issue and FILL OUT the two last points.\n")
+        print(self.format_dict(info))
+
+        return info
+
+    @staticmethod
+    def format_dict(d):
+        return "\n".join([f"- {prop}: {val}" for prop, val in d.items()]) + "\n"

evalkit_tf437/lib/python3.10/site-packages/diffusers/commands/fp16_safetensors.py

@@ -0,0 +1,132 @@
+# Copyright 2024 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+Usage example:
+    diffusers-cli fp16_safetensors --ckpt_id=openai/shap-e --fp16 --use_safetensors
+"""
+
+import glob
+import json
+import warnings
+from argparse import ArgumentParser, Namespace
+from importlib import import_module
+
+import huggingface_hub
+import torch
+from huggingface_hub import hf_hub_download
+from packaging import version
+
+from ..utils import logging
+from . import BaseDiffusersCLICommand
+
+
+def conversion_command_factory(args: Namespace):
+    if args.use_auth_token:
+        warnings.warn(
+            "The `--use_auth_token` flag is deprecated and will be removed in a future version. Authentication is now"
+            " handled automatically if user is logged in."
+        )
+    return FP16SafetensorsCommand(args.ckpt_id, args.fp16, args.use_safetensors)
+
+
+class FP16SafetensorsCommand(BaseDiffusersCLICommand):
+    @staticmethod
+    def register_subcommand(parser: ArgumentParser):
+        conversion_parser = parser.add_parser("fp16_safetensors")
+        conversion_parser.add_argument(
+            "--ckpt_id",
+            type=str,
+            help="Repo id of the checkpoints on which to run the conversion. Example: 'openai/shap-e'.",
+        )
+        conversion_parser.add_argument(
+            "--fp16", action="store_true", help="If serializing the variables in FP16 precision."
+        )
+        conversion_parser.add_argument(
+            "--use_safetensors", action="store_true", help="If serializing in the safetensors format."
+        )
+        conversion_parser.add_argument(
+            "--use_auth_token",
+            action="store_true",
+            help="When working with checkpoints having private visibility. When used `huggingface-cli login` needs to be run beforehand.",
+        )
+        conversion_parser.set_defaults(func=conversion_command_factory)
+
+    def __init__(self, ckpt_id: str, fp16: bool, use_safetensors: bool):
+        self.logger = logging.get_logger("diffusers-cli/fp16_safetensors")
+        self.ckpt_id = ckpt_id
+        self.local_ckpt_dir = f"/tmp/{ckpt_id}"
+        self.fp16 = fp16
+
+        self.use_safetensors = use_safetensors
+
+        if not self.use_safetensors and not self.fp16:
+            raise NotImplementedError(
+                "When `use_safetensors` and `fp16` both are False, then this command is of no use."
+            )
+
+    def run(self):
+        if version.parse(huggingface_hub.__version__) < version.parse("0.9.0"):
+            raise ImportError(
+                "The huggingface_hub version must be >= 0.9.0 to use this command. Please update your huggingface_hub"
+                " installation."
+            )
+        else:
+            from huggingface_hub import create_commit
+            from huggingface_hub._commit_api import CommitOperationAdd
+
+        model_index = hf_hub_download(repo_id=self.ckpt_id, filename="model_index.json")
+        with open(model_index, "r") as f:
+            pipeline_class_name = json.load(f)["_class_name"]
+        pipeline_class = getattr(import_module("diffusers"), pipeline_class_name)
+        self.logger.info(f"Pipeline class imported: {pipeline_class_name}.")
+
+        # Load the appropriate pipeline. We could have use `DiffusionPipeline`
+        # here, but just to avoid any rough edge cases.
+        pipeline = pipeline_class.from_pretrained(
+            self.ckpt_id, torch_dtype=torch.float16 if self.fp16 else torch.float32
+        )
+        pipeline.save_pretrained(
+            self.local_ckpt_dir,
+            safe_serialization=True if self.use_safetensors else False,
+            variant="fp16" if self.fp16 else None,
+        )
+        self.logger.info(f"Pipeline locally saved to {self.local_ckpt_dir}.")
+
+        # Fetch all the paths.
+        if self.fp16:
+            modified_paths = glob.glob(f"{self.local_ckpt_dir}/*/*.fp16.*")
+        elif self.use_safetensors:
+            modified_paths = glob.glob(f"{self.local_ckpt_dir}/*/*.safetensors")
+
+        # Prepare for the PR.
+        commit_message = f"Serialize variables with FP16: {self.fp16} and safetensors: {self.use_safetensors}."
+        operations = []
+        for path in modified_paths:
+            operations.append(CommitOperationAdd(path_in_repo="/".join(path.split("/")[4:]), path_or_fileobj=path))
+
+        # Open the PR.
+        commit_description = (
+            "Variables converted by the [`diffusers`' `fp16_safetensors`"
+            " CLI](https://github.com/huggingface/diffusers/blob/main/src/diffusers/commands/fp16_safetensors.py)."
+        )
+        hub_pr_url = create_commit(
+            repo_id=self.ckpt_id,
+            operations=operations,
+            commit_message=commit_message,
+            commit_description=commit_description,
+            repo_type="model",
+            create_pr=True,
+        ).pr_url
+        self.logger.info(f"PR created here: {hub_pr_url}.")